Use the Figure Below to Answer the Following Questions

Multiple Choice

Use the figure below to answer the following questions.
Table 2.4.1
The planets of Vulcan and Romulus each produce goods X and Y.
The following table gives points on their production possibilities frontiers.

-Refer to Table 2.4.1. For Vulcan, the opportunity cost of producing an additional unit of X is

A) 4 units of Y.
B) 2 units of Y.
C) 2/3 units of Y.
D) 1 unit of Y.
E) dependent upon how many units of X are already produced.