Why Is It Difficult to Fully Understand the Association Between

Why is it difficult to fully understand the association between attachment security during infancy and later functioning?

A) The studies are all correlational.
B) The quality of parent-child interactions tends to remain stable, so associations may only reflect the association between current quality and current child functioning.
C) The studies are all correlational and the quality of parent-child interactions tends to remain stable, so associations may only reflect the association between current quality and current child functioning.
D) None of these reasons contribute to this difficulty.