Efficiency involves:

A) producing output using the least amount of labor.
B) producing output using the least amount of capital.
C) producing as far inside the production possibilities frontier as possible.
D) producing only one out of many possible commodities.
E) getting the maximum possible output from available resources.

Efficiency means getting the maximum possible output from available resources. Options A and B are too restrictive as they only focus on labor or capital, and option D is not efficient as it only produces one commodity. Option C is not necessarily efficient as producing too far inside the production possibilities frontier means wasting resources that could be used to produce more goods and services.