If d is the diameter of a bar, ft is allowable tensile stress and fb, is allowable bond stress, the bond length is given by

• A. <img src="/_files/images/civil-engineering/rcc-structures-design/88-13-225-1.png">
• B. <img src="/_files/images/civil-engineering/rcc-structures-design/88-13-225-2.png">
• C. <img src="/_files/images/civil-engineering/rcc-structures-design/88-13-225-3.png">
• D. <img src="/_files/images/civil-engineering/rcc-structures-design/88-13-225-4.png">