As a 7-Year-Old Child, You Helped Your Father Nail a Birdhouse

As a 7-year-old child, you helped your father nail a birdhouse 7 feet high on a 10 -foot-tall maple tree. If the tree grew an average of 12 inches per year, except during a dry year when it grew only 2 inches, how high in the tree is the birdhouse when you are 18 years old?

A) 17 feet, 2 inches
B) 19 feet
C) 10 feet
D) 7 feet
E) 17 feet