The correct option is B.
Here's the breakdown of the cost calculation:
15 cakes:
Cake mix: $2.50 x 15 = $37.50
Baking pans: $62
Total: $37.50 + $62 = $99.50
30 cakes:
Cake mix: $2.50 x 30 = $75
Baking pans: $62
Total: $75 + $62 = $137
50 cakes:
Cake mix: $2.50 x 50 = $125
Baking pans: $62
Total: $125 + $62 = $187
So the correct option is B