Determine whether the stated causal connection is valid. If the causal connection appears to bevalid, provide an explanation.

Test grades are affected by the amount of time and effort spent studying and preparing for the test.

Choose the correct answer below.

A.

The causal connection is valid. When students spend more time and effort studying for atest, their test grades tend to be higher.

B.

The causal connection is valid. Students who spend more time and effort studying tend to besmarter, so their test grades are higher.

C.

The causal connection is not valid.

D.

The causal connection is valid. Students who spend more time and effort studying will be able to memorize moreinformation, so their test grades will be higher.