Question

No quiero cocinar la cena, ___________________ tú.

Answer 1

No quiero cocinar la cena
Hazla tú

Answer 2

No quiero cocinar la cena, _________ tú.

Translation:

I don't want to cook dinner, [blank] you."

To use the correct conjugation of the verb, know the subject. Here it is la cena, which is feminine singular. Only one of the options provided is both feminine and singular.

a. hazla - "do it" (feminine singular)
b. hazlo - "do it" (masculine singular)
c. hazlas - "do it" (feminine plural)

Answer:
a. hazla

No quiero cocinar la cena, hazla tú.