P is the prestressed force applied to tendon of a rectangular prestressed beam whose area of cross section is A and sectional modulus is Z. The minimum stress f on the beam subjected to a maximum bending moment M is

• A. <img src="/_files/images/civil-engineering/rcc-structures-design/86-13-204-1.png">
• B. <img src="/_files/images/civil-engineering/rcc-structures-design/86-13-204-2.png">
• C. <img src="/_files/images/civil-engineering/rcc-structures-design/86-13-204-3.png">
• D. <img src="/_files/images/civil-engineering/rcc-structures-design/86-13-204-4.png">
• E. <img src="/_files/images/civil-engineering/rcc-structures-design/86-13-204-5.png">