The Figure Below Shows Production Possibilities Curves for Tomatoes and Oranges

The figure below shows production possibilities curves for tomatoes and oranges in two prefectures in a country.

-Refer to the figure above.In Prefecture A,the opportunity cost of producing each additional pound of tomatoes ________.

A) increases as more tomatoes are produced
B) stays the same as more tomatoes are produced
C) decreases as more tomatoes are produced
D) increases up to 1 billion (1,000 million) pounds and then decreases after 1 billion pounds