Zachary is 3 feet 8 inches tall. If Zachary grows another 1 foot 9 inches, he will be as tall his mother. If Zachary grows another 2 feet 6 inches, he will be as tall as his father. How tall is Zachary's father?
a. 5 feet 5 inches
b. 5 feet 9 inches
c. 6 feet 2 inches
d. 6 feet 4 inches