If Countries a and B Produce Only Either Rubber Bands

Multiple Choice

If countries A and B produce only either rubber bands or paper clips, their maximum outputs are shown in the accompanying production possibilities schedules.
$$\begin{array} { | c | c | c | } \hline \text { Country } & \text { Rubber Bands } & \text { Paper Clips } \\\hline A & 40 & 80 \\\hline B & 10 & 40 \\\hline\end{array}$$ In country A the opportunity cost of 1 paper clip is

A) 2 rubber bands.
B) 1 rubber band.
C) $1 / 2$ 1/2 rubber band.
D) $1 / 4$ 1/4 rubber band.