92；The supply of oil being finite has become an economical and political consideration of the first magnitude for all modern industrial nations.

(A) The supply of oil being finite has become an economical

(B) The finite supply of oil has become an economical

(C) That the supply of oil is finite has become an economical

(D) The supply of oil being finite has become an economic（E）

(E) That the supply of oil is finite has become an economic

e对没意见；请问b错在哪里，有限的石油供应不是挺顺的么，还是...supply ..is an..consideration这样的表达有误？

另：请教主语从句，连词that是否不可省？