An Advantage of a Within-Subjects Design Over a Matched-Pairs Between-Subjects

Multiple Choice

An advantage of a within-subjects design over a matched-pairs between-subjects design is that:

A) in the within-subjects design, it is easier to measure and take into account relevant subject characteristics.
B) measuring subject characteristics is unnecessary in a within-subjects design.
C) error variance is totally eliminated in the within-subjects design.
D) it is easier to measure and take into account relevant subject characteristics, and error variance is totally eliminated.