[求助]再问大全650，on the other hand多余？

650.Since savings banks have to use short-term deposits to finance long-term fixed-rate mortgage loans, they sometimes lose money when there is a rise in short-term rates and, on the other hand, they are unable to raise the rates on their mortgages.

(A) when there is a rise in short-term rates and, on the other hand, they are unable to raise

(B) when short-term rates rise and they are unable to raise

(C) when a rise in short-term rates occurs and, correspondingly, there is no rise possible in

(D) with a rise in short-term rates, and they are unable to raise（B）

(E) with short-term rates on the rise and no rise possible in

大全的答案是B。我选A。

A虽然罗嗦，但是保留了原句中转折的意思，而大全注释说，A中on the other hand多余，不理解了，求助ing~~~~~

我的理解是：

on the other hand表示另一方面，意思上是可以等同于and的。