Question

i ----(cook) food since six'o' clock​

Answer 1

Answer:

I am cooking food since six o'clock.

Answer 2

Answer:

I have been cooking food since six 'o' clock .

Explanation:

With Present Perfect Continuous , for/ since is used.

Hence , in the sentence since is used so we will use the helping verb of Present Perfect Continuous.

Hope it will help you ^_^