Doing morning exercise is of great _____ to your health & consequently you'd better keep on it.[ ]

A. benefit

B. beneficial

C. benefition

D. useful

我国房地产业主要的法律法规体系中主要的3部法律是《中华人民共和国土地管理法》、《城市房地产管理法》和《闲置土地管理办法》。