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