A Builder Has Agreed Not to Erect All "Look Alike

Multiple Choice

A builder has agreed not to erect all "look alike" homes in a new subdivision. Five exterior designs
Are offered to potential homebuyers. The builder has standardized three interior plans that can be
Incorporated in any of the five exteriors. How many different ways are the exterior and interior plans
Offered to potential homebuyers?

A) 8
B) 10
C) 15
D) 30