The position of a sprinter at the starting blocks is shown in the diagram. Given that angle 1 and angle 4 are right angles, which statement can be proved?
(Picture included.)
A. <3 is congruent to <5
B. m<1 + m<4 = 90 degrees
C. m<3 + m<5 =180 degrees
D. <1 is congruent to <4