The correct answer is B.
Rwanda was first colonized by the Germans, and later on by the Belgish (1922-1962), right after the revolution (1959-1962) which ended with the independency and the creation of the Republic of Rwanda.
The colonizers believed the Tutsi were a superior race, if compared to the others in the country, as they perceived them to be more similar to the Europeans. They prefered them due to their taller height, finer manners, eloquent personalities, and due to the willingness to convert to Roman Catholicism. The Tutsis were favoured by them, and given ruling positions over the the farmer Hutus.
Tutsis only comprised around the 15% of the population but composed the majority of the ruling elites