Frame ‘wh’ question for the given sentence:
Mother is cooking food in the kitchen.

Concept: Option A is impeccably answered by the statement in the question. It indicate the venue where the mother is cooking the food. So, option A is correct.

• Option B will be answered by a yes or by a no. yes, the mother is cooking the food or no, the mother is n’t cooking the food. So, this option is incorrect.
• Option C would be answered specifying the action of the mother but the statement in the question gives further information than that. So, this option is also incorrect.
• Option D is like a evidence question attesting about the venue where the mothet is and no inclination is given to what she's doing. So, option d is also incorrect.

Hence, option A is the correct answer.