As we know that ,
base is anything low, ordinary,
Concise means short or compact,
Partial is not complete, and Insist is to make a request.

Correct Option: A

As we know that ,
Sublime is magnificent and great, base is anything low, ordinary, concise means short or compact, partial is not complete, and Insist is to make a request.
Therefore , required word is base .

As we know that ,
Primitive means of the very old time, and thus not very developed or refined, Naive means inexperienced.

Correct Option: D

As we know that ,
Primitive means of the very old time, and thus not very developed or refined, sophisticated is well-refined and well mannered, Naive means inexperienced.
Hence , sophisticated is antonym of Primitive .

As we know that,
Reverse, Relapse and Retreat all mean going back. Regenerate on the other hand means to create a new life, go ahead.

Correct Option: C

As we know that ,
Regression means to go back or return; reverse, relapse and retreat all mean going back. Regenerate on the other hand means to create a new life, go ahead. Thus is the antonym.
Therefore , Regenerate is antonym of Regression .

As we know that ,
Salutatory is the welcome speech and valedictory is a farewell speech, derivative means something that has been derived from another.

Correct Option: A

As we know that ,
Salutatory is the welcome speech and valedictory is a farewell speech, derivative means something that has been derived from another.
Hence , Sad is antonym of word Salutatory .

Fervent, similar to fever, fervour means showing enthusiasm.

Correct Option: B

Fervent, similar to fever, fervour means showing enthusiasm.