Because cellular telephones emit signals that can interfere

[BTGmoderatorDC]

Because cellular telephones emit signals that can interfere with cockpit-to-control-tower transmissions, airplane passengers' use of these instruments at all times that the airplane is in motion, even while on the ground, are prohibited.

(A) at all times that the airplane is in motion, even while on the ground, are

(B) at all times during which the airplane, even while on the ground, is in motion, are

(C) during airplane motion, even when it is on the ground, are

(D) during times of the airplane being in motion, even on the ground, is

(E) when the airplane is in motion, even while on the ground, is

OA E

Source: Princeton Review

[SnigdhaD]

Because cellular telephones emit signals that can interfere with cockpit-to-control-tower transmissions, airplane passengers' use of these instruments at all times that the airplane is in motion, even while on the ground, are prohibited.

(A) at all times that the airplane is in motion, even while on the ground, are
WRONG that after all times is a wrong grammar, passengers' use is singular while are prohibited is plural

(B) at all times during which the airplane, even while on the ground, is in motion, are
WRONG same verb error as A

(C) during airplane motion, even when it is on the ground, are
WRONG Same verb error as A

(D) during times of the airplane being in motion, even on the ground, is
WRONG being in motion, even on the ground does not sound meaningful or right with the actual meaning of the sentence

(E) when the airplane is in motion, even while on the ground, is
CORRECT NO verb error or changed meaning and when correctly modifies all times