If R and T are rise and tread of a stair spanning horizontally, the steps are supported by a wall on one side and by a stringer beam on

If R and T are rise and tread of a stair spanning horizontally, the steps are supported by a wall on
one side and by a stringer beam on the other side, the steps are designed as beams of width

(A) R + T

(B) T - R

(C) 2 + T2

(D) R - T

The correct Answer Is
(C) 2 + T2