IN THE MIDDLE OF OUR LUNCH, THERE WAS A KNOCK AT THE DOOR. A. WHEN...

87. In the middle of our lunch, there was a knock at the door.

A. When we were having lunch, there was a knock at the door.

B. Our lunch were in the middle there was a knock at the door.

C. When we had just finished lunch, there was a knock at the door.

D. When they knock at the door, we were having lunch.