A candy store sells a bag of cotton candy for $0.70 and chocolate bars for $0.50. Sheila bought some cotton candy and several chocolate bars from the store and spent a total of $6.30. How many bags of cotton candy and bars of chocolate did Sheila purchase?

A 4

B 7

C 11

D 13

E 17

Let us assume number of bags of cotton candies and chocolate bars = x.

Cost of each a bag of cotton candy = $0.70.

Cost of each chocolate bar = $ 0.50.

Total cost of x bags of cotton candies = 0.70 x.

Total cost of x chocolate bars = 0.50x.

Total cost of all items = $6.30.

0.70 x + 0.50x = 6.30.

1.20x = 6.30.

Dividing both sides by 1.20, we get

1.20x/1.20 = 6.30/1.20

x = 5.25.

Total number of bags of cotton candies + number of chocolate bars = 5.25 + 5.25 = 10.50 ≈ 11 approximately.

Therefore, correct option is C. 11.