We Observe That Both the Price of and Quantity Sold

We observe that both the price of and quantity sold of golf balls are rising over time. This is due to:

A) continual improvements in the technology used to produce golf balls.
B) increases in the price of golf clubs over time.
C) decreases in membership fees for country clubs with golf facilities.
D) more stringent professional requirements on the quality of golf balls requiring producers to use more expensive raw materials.