The correct answer is letter C.
Charles Spearman was an English psychologist who was born on September 10, 1863 and died on September 7, 1945.
He began his activity as a psychologist after the age of 15 as a British Army officer. Years later, he left this position to go to university in Germany.
One of his most important studies as a psychologist is the bifactorial theory of intelligence.
Charles Spearman believed that all intelligent behavior was based on a general factor, which he called the G factor.
This G factor, in the bifactorial theory of intelligence, is the basis of all other factors and where they all come from.
