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. <img src="/_files/images/civil-engineering/rcc-structures-design/85-13-193-1.png">
• B. <img src="/_files/images/civil-engineering/rcc-structures-design/85-13-193-2.png">
• C. <img src="/_files/images/civil-engineering/rcc-structures-design/85-13-193-3.png">
• D. <img src="/_files/images/civil-engineering/rcc-structures-design/85-13-193-4.png">
• E. <img src="/_files/images/civil-engineering/rcc-structures-design/85-13-193-5.png">