If angle C is a right angle and angle A equals 50, then prove that the measure of angle B equals 40" Which of the following would be the first step to assume in order to prove the statement above by contradiction using an indirect prool?

A)The measure of angle B does not equal 40°

B)The measure of angle A equals 50

C)The measure of angle B equals 40

D)Angle C is not a night angle.

E)Angle C is a right angle

IM GIVING 15 POINTS