Which of the following is NOT a problem associated with observational studies?

A) They cannot determine cause and effect relationships.
B) The subjects may behave differently when they know they are being observed.
C) It is not possible to gain information regarding relationships between variables.
D) Laboratory studies may not generalize to real life.

Observational studies are commonly used to gather information about relationships between variables, but they do have limitations, such as the inability to establish cause-and-effect relationships. Other issues associated with observational studies include bias, confounding factors, and limited control over confounding variables. However, these do not include the inability to gain information regarding relationships between variables. Therefore, option C is not a problem associated with observational studies.