Which sentence is grammatical?

✂️ a) The principal insists that the new student signs up for a counselor.

✂️ b) The customer demanded that the store returned his money.

✂️ c) The doctor recommended that Kate will stop drinking soda.

✂️ d) The supervisor suggested that the engineer see the blue prints.

✂️ e) They requested that we are on time for the meeting.

Responda: Which sentence is grammatical?