One Possible Explanation for Spearman's "G" Factor Is That

Multiple Choice

One possible explanation for Spearman's "g" factor is that

A) most of the early IQ tests had very low reliability.
B) health and other influences that improve one ability also improve other independent abilities.
C) extra development of one ability decreases the possibility for developing other abilities.
D) different parts of the brain develop at different times, depending on different genes.