You cannot lose what you never had is a Proverb : you should not have lost something if you only wished that you had it to begin with
Look at the sentence :
Mary was never your girl-friend. You haven’t lost what was never yours.
Here, never is the right usage.

Correct Option: C

You cannot lose what you never had is a Proverb : you should not have lost something if you only wished that you had it to begin with
Look at the sentence :
Mary was never your girl-friend. You haven’t lost what was never yours.
Here, never is the right usage.

fair (Adj.) : of pleasing appearance ; acceptable and appropriate in a particular
situation
fare (V.) : to be successful in a particular situation → fare well/ badly/better, etc.
flare (V.) : to burn brightly, but usually for only a short time/ not steadily
None but the brave (only the brave) deserve the fair is a
Proverb : only the best deserve
the best ; only a courageous and gallant man deserves a beautiful woman
Here, fair is the right usage.

Correct Option: D

fair (Adj.) : of pleasing appearance ; acceptable and appropriate in a particular
situation
fare (V.) : to be successful in a particular situation → fare well/ badly/better, etc.
flare (V.) : to burn brightly, but usually for only a short time/ not steadily
None but the brave (only the brave) deserve the fair is a
Proverb : only the best deserve
the best ; only a courageous and gallant man deserves a beautiful woman
Here, fair is the right usage.

revenge (N.) : something that you do in order to make somebody suffer because he has made you suffer
avenge (V.) : to punish/hurt somebody in return for something bad/wrong that he has done to you, your family/ friends (to avenge)
vengeance (N.) : the act of punishing/harming somebody in return for what he has done
to you, your family/friends (to take vengeance)
ravage (V.) : to damage something badly
As take (V.) has been used, revenge is the right usage

Correct Option: C

revenge (N.) : something that you do in order to make somebody suffer because he has made you suffer
avenge (V.) : to punish/hurt somebody in return for something bad/wrong that he has done to you, your family/ friends (to avenge)
vengeance (N.) : the act of punishing/harming somebody in return for what he has done
to you, your family/friends (to take vengeance)
ravage (V.) : to damage something badly
As take (V.) has been used, revenge is the right usage

look up (Phr. V.) : to look for information (dictionary/ reference book/computer).
look down on (Phr. V.) : to think that you are better than somebody/something
look into (Phr. V.) : to examine something
look after (Phr.V. ) : to be responsible for or to take care of somebody/something
Here, look up is the right usage.

Correct Option: B

look up (Phr. V.) : to look for information (dictionary/ reference book/computer).
look down on (Phr. V.) : to think that you are better than somebody/something
look into (Phr. V.) : to examine something
look after (Phr.V. ) : to be responsible for or to take care of somebody/something
Here, look up is the right usage.

Here, assured is the right usage.

Correct Option: D

Here, assured is the right usage.