Use the Following Scenario to Answer Thefollowing Questions

Use the following scenario to answer thefollowing questions:
An economy has two workers,Smith and Ricardo.Each day they work,Smith can produce 4 computers or 16 smartphones,and Ricardo can produce 6 computers or 12 smartphones.
-The opportunity cost for Ricardo to produce one computer is ________ smartphone(s) .

A) one-quarter of a
B) one-half of a
C) one
D) two
E) four