The economical depth d of a web plate in which allowable bearing stress is fb, and the maximum bending moment is M, as suggested by Rawater and Clark, is

• A. <img src="/_files/images/civil-engineering/steel-structure-design/105-14-164-1.png">
• B. <img src="/_files/images/civil-engineering/steel-structure-design/105-14-164-2.png">
• C. <img src="/_files/images/civil-engineering/steel-structure-design/105-14-164-3.png">
• D. <img src="/_files/images/civil-engineering/steel-structure-design/105-14-164-4.png">
• E. <img src="/_files/images/civil-engineering/steel-structure-design/105-14-164-5.png">