【单选题】

Although he was______in his efforts to persuade us of the justness of his cause, his past history,______with failures, prevented us from being any more than skeptical at his words.
A．(A) tireless… marred

B．(B) sage… coupled
C．(C) resourceful . . . immaculate
D．(D) unassuming … tinged
E．(E) unyielding … touched