If is the surcharge angle of a backfill with an angle of internal friction , the coefficient of active earth pressure given by Rankine's theory, is :

• A. <img src="/_files/images/civil-engineering/soil-mechanics-and-foundation-engineering/39-11-134-1.png">
• B. <img src="/_files/images/civil-engineering/soil-mechanics-and-foundation-engineering/39-11-134-2.png">
• C. <img src="/_files/images/civil-engineering/soil-mechanics-and-foundation-engineering/39-11-134-3.png">
• D. none of these.