The Formula Which Uses Chronological Age (CA) and Mental Age $\div$

Multiple Choice

The formula which uses chronological age (CA) and mental age (MA) to calculate the intelligence quotient is:

A) MA $\div$ CA $\times$ 100.
B) CA $\div$ MA $\times$ 100.
C) (MA $\times$ CA) $\div$ 100.
D) 100 $\div$ (MA + CA) .