Sentence Correction

Good day
Lacking information about energy use, people tend
overestimate the amount of energy used by equipmt
such as lights, that are visible and must be turned o
and off and underestimate that used by unobtrusive
equipment, such as water heaters.
(A) equipment, such as lights, that are visible and
must be turned on and off and underestimate
(B) equipment, such as lights, that are visible and
must be turned on and off and underestimate
when
(C) equipment, such as lights, that is visible and m
be turned on and off and underestimate it whe
(D) visible equipment, such as lights, that must b
turned on and off and underestimate that
(E) visible equipment, such as lights, that must b
turned on and off and underestimate it when
the OA is D but my question is:
Aequipment, such as lights, that are visible and
must be turned on and off and underestimate that
to correct this answer we need to add a "that" in front of must be+(is instead of are)
Am I' correct??
Many thanks in advance

i really don't think that it will correct that sentence
for 3 reason :
A) visible equipments is much better than equipments that are visible
B)if u really add that "that" u will be implying parallelism between these two stuff( equipment, such as lights, that are visible and that must be turned on and off) when in first place u don't need any
C)also with so many "and" the structure will appear clumsy

First, let me clean up the formatting a little for anyone else who wants to try the question

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.

(A) equipment, such as lights, that are visible and must be turned on and off and underestimate

(B) equipment, such as lights, that are visible and must be turned on and off and underestimate when

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

(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

Amadalia wrote: the OA is D but my question is:
Aequipment, such as lights, that are visible and
must be turned on and off and underestimate that
to correct this answer we need to add a "that" in front of must be+(is instead of are)
Am I' correct??
Many thanks in advance

I don't think you need the extra that. It would be fine as:

equipment, such as lights, that is visible and must be turned on and off

Equipment that:
1. is visibile
2. must be turned on and off