6. What is the future perfect third-person conjugation for the irregular verb become? he, she, It will have become he, she, it will become he, she, it will have became you will become

I am not sure how to read your choices but the future perfect third person is

he or she will have followed by the past tense of a verb. You have to read that a couple of times to get it right.

Perfect means the action will be completed some time in the future.

Third person is he she it. (in the singular form.)

he will have become a grandmaster chess player by that time, would be a correct use of the verb become.