Big Al's Snack Stand sells burgers and sandwiches. Big Al puts two tomato slices on each burger and four tomato slices on each sandwich. If he sells b burgers and s sandwiches, which expression represents the number of tomato slices that he will use?

A.

2s + 4b

B.

2b × 4s

C.

(b + 2) × (s + 4)

D.

2b + 4s