Assume that a consumer has a given budget or income of $12 and that she can buy only two goods, apples or bananas. The price of an apple is $1.50 and the price of a banana is $0.75.

For this consumer, the opportunity cost of buying one more apple is :

a)0.5 of a banana.

b)2 bananas.

c)0.8 of a banana.

d)1 banana.