The Cost Function for Producing a New Book Is $C ( x ) = 8.5 x + 1200$

The cost function for producing a new book is $C ( x ) = 8.5 x + 1200$ . The average cost for producing this book is $\mathrm { A } ( x ) = \frac { C ( x ) } { x }$ . If 150 books are produced, what is the average cost of producing this book?

A) $16.50
B) $14.50
C) $12.50
D) $18.50