If an economy is producing efficiently and has chosen to produce and consume 12 units of X and...

If an economy is producing efficiently and has chosen to produce and consume 12 units of X and 128 units of Y. At this point on the production possibilities frontier, one can use calculus to obtain the opportunity cost of Y as:

A) -12

B) -6

C) 0

D) {eq}\frac{1}{6} {/eq}

E) 3

F) {eq}4 \frac {1}{3} {/eq}

G) 5

H) 6

J) none of the above

1) 8