【单选题】

The teacher has______catering to some students, but to retain his tenure, which effects only after a teacher has unanimously gratified his students, he offers his complaints______.
A．(A) a hesitancy about … carelessly

B．(B) an aptitude for … sparingly
C．(C) a repugnance toward … tactfully
D．(D) an enthusiasm about … zealously
E．(E) a blitheness about … carefully