If T and R are the tread and rise of a stair which carries a load w per square metre on slope, the
corresponding load per square metre of the horizontal area, is
(A) w (R + T)/T
(B) w (R² + T²)/T
(C) w (R + T)/T
(D) w (R/T)
corresponding load per square metre of the horizontal area, is
(A) w (R + T)/T
(B) w (R² + T²)/T
(C) w (R + T)/T
(D) w (R/T)