The table identifies how many thousands of units of corn and diamonds the United States and Congo can produce in one week. Use this data to answer the question that follows.


Corn Diamonds

United States
60 10

Congo
20 5

Which fraction represents the opportunity cost for the United States to produce corn?
A. 60⁄10
B. 10⁄60
C. 20⁄5
D. 5⁄20