For columns whose slenderness ratio is upto 160, the secant formula for the determination of allowable stress, is

• A. <img src="/_files/images/civil-engineering/steel-structure-design/96-14-59-1.png">
• B. <img src="/_files/images/civil-engineering/steel-structure-design/96-14-59-2.png">
• C. <img src="/_files/images/civil-engineering/steel-structure-design/96-14-59-3.png">
• D. <img src="/_files/images/civil-engineering/steel-structure-design/96-14-59-4.png">