Allocating Products with Long Lines, Using a First-Come, First-Served System

Allocating products with long lines, using a first-come, first-served system, is:

A) the only way scarce goods can be allocated.
B) necessary when waiting is a costless exercise.
C) efficient, since people who are willing to wait the longest get the products.
D) inefficient, because waiting wastes time.(True Answer ) Correct