求助OG10,SC 第139题~

139. The extraordinary diary of William Lyon Mackenzie King, prime minister of Canada for over twenty years, revealed that this most blandand circumspect of men was a mystic guided in both public and private life by omens, messages received at seances, and signs from heaven.

(A)that this most bland and circumspect of men was a mystic guided in both public and

(B)that this most bland and circumspect of men was a mystic and also guided both in public as well as

(C)this most bland and circumspect of men was a mystic and that he was guided in both public and

(D)
                            this most bland and circumspect of men was a
                        mystic and that he was guided in both public
                        as well as

(E)
                            this most bland and circumspect of men to have
                        been a mystic and that he guided himself
                        both in public as well as

想知道this most bland and ...of men中的of是什么用法？ 形容词+of+名词？？

还有was a  mystic guided...was A mystic guided? 为什么要用a.?

谢谢大牛们~