Grammar

Hello everyone,

Is either "of" or "for" correct in the following sentences?

1. The correct tag question of/for "He is playing" is.....

A. isn't he? B. is he? C. Was he? D. none of them

2. The tag question of/for "He is playing" is.......

A. isn't he? B. is he? C. was he? D. none of them

I think "for" is correct.??

Regards,

Joseph