Which of the Following Was NOT Among the Factors in the Decline

Which of the following was NOT among the factors in the decline of the Islamic empires?

A) a series of weak and incompetent rulers
B) a collapse in the centuries-old civil service examination system
C) rising tensions between different religious groups
D) changing trade routes that bypassed the empires and hurt them financially
E) increasing religious conservatism and intolerance among the Islamic leaders