题目

While a man was passing by an elephant, he suddenly stopped. The elephant was held by only a small rope. The farmer ties the rope to the elephant's front leg. No chains, no cages. The man was very confused. He wanted to know why the elephant didn't run away.He visited the farmer and asked why the elephant just stood there and didn't run away. Well, the farmer said, when it was very young and much smaller, we used the same size rope to tie it. At that age, the rope was strong enough to hold it. Of course it couldn't run away. When it grew up, it still believed the rope could hold it. So it neve12．如图，某几何体的三视图是三个半径相等的圆及每个圆中两条互相垂直的半径．若该几何体的体积是$\frac{224π}{3}$，则它的表面积是（　　）A．17πB．18πC．60πD．68π