Each group of sentences below could be organized into and written as a paragraph. In each group, select the letter of the topic sentence. Which sentence is the topic sentence?

A) Here at Kensington College, without our student numbers, we would hardly exist.
B) We must display our student numbers and our IDs just to get onto campus.
C) We must pencil our student numbers on computer cards in order to register for courses.
D) When our grades are posted, the A's and F's go not to Felicia Watson and Bill Jenkins, Jr., but to 237-0002 and 235-1147.