Question

each of these relationships reflects a correlation. which relationship most likely reflects both correlation and causation?
drinking iced coffee more often is associated with consuming more caffeine.
drinking iced coffee more often is associated with using a fan more often.
drinking iced coffee more often is associated with wearing shorts more often.

Explanation:

Iced coffee contains caffeine. So, drinking it more often directly leads to consuming more caffeine, showing both correlation and causation. The other two relationships (using a fan more often and wearing shorts more often) are likely just correlated with hot weather which might also make people drink iced - coffee more often, but there is no direct causal link between iced - coffee and those activities.

Answer:

Drinking iced coffee more often is associated with consuming more caffeine.