.... has primarily led to the growth of Islamic reform movements in many sub-Saharan African countries

A.

The crisis of modernisation of the 20th Century

B.

The new discoveries on the inadequacies of Islam

C.

The shift in the belief and religious system of Islam

D.

The rigidity in the use of Arabic language

Correct answer is A

The crisis of modernisation of the 20th century is the correct answer. Islamic reform movements developed majorly in response to the challenges of social development (e.g. the Mosques are often known as platforms for criticism of the shortcomings of the African government regimes), educational reform (e.g. training as religious scholars), and the popularisation of Islamic values.