Why Is the Range Effect Known as a "Ceiling Effect

Multiple Choice

Why is the range effect known as a "ceiling effect" a problem for researchers?​

A) ​The scores are already so high that there is no chance of measuring improvement.
B) ​The scores are already so low that there is no chance of measuring a decrease.
C) There is so much room for improvement that the measurements are almost certain to   increase.
D) ​There is so much room for lower performance that the measurement are almost certain   to decrease.