befog (Verb) : to make somebody confused
enlighten (Verb) : to give somebody information so that he may understand something better
slander (Verb) : to make a false spoken statement about somebody that is intended to damage the good opinion that people have of him
bemoan (Verb) : to complain or say that you are not happy about something
darken (Verb) : to become dark ; to make something dark ; to become/make somebody unhappy or angry

Correct Option: D

befog (Verb) : to make somebody confused
enlighten (Verb) : to give somebody information so that he may understand something better
slander (Verb) : to make a false spoken statement about somebody that is intended to damage the good opinion that people have of him
bemoan (Verb) : to complain or say that you are not happy about something
darken (Verb) : to become dark ; to make something dark ; to become/make somebody unhappy or angry

retarded (Verb) : made the development or progress slower
advanced (Verb) : developed and improved
progressed (Verb) : improved or developed over a period of time; advanced
outpaced (Verb) : went, rose, improved etc. faster than somebody/something ; outstripped
receded (Verb) : moved gradually away from somebody or away from a previous position ; became gradually weaker and smaller

Correct Option: D

retarded (Verb) : made the development or progress slower
advanced (Verb) : developed and improved
progressed (Verb) : improved or developed over a period of time; advanced
outpaced (Verb) : went, rose, improved etc. faster than somebody/something ; outstripped
receded (Verb) : moved gradually away from somebody or away from a previous position ; became gradually weaker and smaller

tuneless (Adjective) : not having a pleasant tune or sound
melodious (Adjective) : pleasant to listen to
harmonious (Adjective) : friendly, peaceful and without any disagreement ; very pleasant when played or sung together
odious (Adjective) : extremely unpleasant ; horrible
mellifluous (Adjective) : sounding sweet and smooth ; very pleasant to listen to

Correct Option: B

tuneless (Adjective) : not having a pleasant tune or sound
melodious (Adjective) : pleasant to listen to
harmonious (Adjective) : friendly, peaceful and without any disagreement ; very pleasant when played or sung together
odious (Adjective) : extremely unpleasant ; horrible
mellifluous (Adjective) : sounding sweet and smooth ; very pleasant to listen to

lavishly (Adverb) : luxuriously ; extravagantly ; spend generously
niggardly (Adjective) : unwilling to be generous with money, time etc. ; mean ; miserly
hastily (Adverb) : hurriedly ; very quickly
likely (Adverb) : very probably
gorgeously (Adverb) : very beautifully and attractively ; impressively

Correct Option: B

lavishly (Adverb) : luxuriously ; extravagantly ; spend generously
niggardly (Adjective) : unwilling to be generous with money, time etc. ; mean ; miserly
hastily (Adverb) : hurriedly ; very quickly
likely (Adverb) : very probably
gorgeously (Adverb) : very beautifully and attractively ; impressively

lands (Verb) : comes down through the air onto the ground or another surface takes
off (Idiom) : leaves the ground and begins to fly ; to become successful or popular very quickly or suddenly
travels (Verb) : to go from one place to another, over a long distance
falls (Verb) : drops down from a higher level to a lower level ; suddenly stops standing ; decreases down in amount, number or strength
explodes (Verb) : bursts or makes something burst loudly and violently, causing damage

Correct Option: D

lands (Verb) : comes down through the air onto the ground or another surface takes
off (Idiom) : leaves the ground and begins to fly ; to become successful or popular very quickly or suddenly
travels (Verb) : to go from one place to another, over a long distance
falls (Verb) : drops down from a higher level to a lower level ; suddenly stops standing ; decreases down in amount, number or strength
explodes (Verb) : bursts or makes something burst loudly and violently, causing damage