Charles Spearman's G Factor Conception of Intelligence and L

Charles Spearman's g factor conception of intelligence and L.L. Thurstone's primary mental abilities conception of intelligence are similar in that:

A) they both argued that the various specific mental abilities were the most important to determine intelligence.
B) they are both examples of the cognitive processes approach to intelligence.
C) they were both based on the same correlations among mental tasks measured by IQ tests.
D) they both argued that a single general intelligence factor was most important to determine intelligence.