Which of these was NOT the cause responsible for crisis of the Mughal Empire towards the closing year of the 17th century?
a) Emperor Aurangzeb had depleted the military and financial resources of his empire by fighting a long war in the Deccan.
b) Under Aurangazeb's successors, the efficiency of the imperial administration became more strong .
c) It was increasingly difficult for the later Mughal emperors to keep a check on their powerful mansabdars.
d) Nobles appointed as governors (subedars) often controlled the offices of revenue and military administration (diwani and faujdari) as well.