________ is known to us all that the old scientist, for ________ life was hard in the past, still works very hard in his eighties.[ ]

A．It; whom 

B．As; whom

C．As; whose  

D．What; whom

调查主责任人对有权审批人审批的信贷业务的发生后监管、本息收回和债权保全负责