The correlational method of research compares

A) the relationship between multiple variables.
B) the relationship between children, adolescents and adults.
C) the relationship between several cultures and ethnic populations.
D) the relationship between two variables.

The correlational method involves examining the relationship between two variables. Therefore, the best choice is D, as it accurately describes the method of research. A, B, and C all include multiple variables or groups, which would require a different research method (such as multivariate analysis or cross-cultural studies).