The boy _____ the foreign stamps he had collected.
A.is sorting B.has been sorted
The boy is sorting the foreign stamps he had collected.
这男孩（正在)整理他收集的外国邮票.
如果是B的话就变成..
The boy has been sorted the foreign.也就是
这男孩被整理他收集的.
那么就doesn't make sense了 因为has been 有‘被’怎样怎样的意思 而在这里 不适用