Concept:The key feature of Al-Hajj Umar Tall's Islamic reform movement was its goal of creating a purely Islamic state governed by Islamic law.
Explanation:Al-Hajj Umar Tall led a religious and political movement in the 19th century.
He aimed to spread Islam and establish a government based on strict Islamic principles.
His efforts led to the creation of a theocratic state, which means a state ruled by religious leaders according to Islamic law.
This state was centred in Senegal and extended into the western Sudan region.
His movement did not focus on Western education, alliances with European powers, or commercial agriculture with Europe.
Therefore, the movement is best characterized by the establishment of a theocratic state.
Answer:D. The establishment of a theocratic state in Senegal and the western Sudan.