A Researcher Tests the Memories of Groups Who Are 40,60,and

Multiple Choice

A researcher tests the memories of groups who are 40,60,and 80 years old,and finds the youngest group better able to memorize information.The researcher concludes memory ability declines with age.You should assume the researcher's conclusion is

A) valid, due to sequential effects.
B) invalid, due to sequential effects.
C) valid, due to cohort effect.
D) invalid, due to cohort effect.