Lacking information about energy use, people tend to overestimate the amount of energy used by
equipment. such as lights, that are visible and must be turned on and off and underestimate that used by unobtrusive equipment, such as water heaters.

(D) visible equipment, such as lights, that must be turned on and off and underestimate that
(E) visible equipment, such as lights, that must be turned on and off and underestimate it when

Here I choose E because it is wrong. why?