The correct answer should be both a and b
While the imperialists had guns and weaponry like that, many African people still fought with spears, which often made it easy to conquer them. Of course, there were exceptions, especially when it comes to Britain, where they just couldn't defeat the locals. Their industry didn't exist and was undeveloped.
This type of vote is know as a Plebiscites
Americans were searching for natural gold and new resources. Some believed the Indians were keeping these resources for themselves. Many Indians were evicted during this time.
The colonial policies and practices that played a part in peaceful or violent transitions to self-rule were very complex. One major one which had a very important role here was Apartheid. This was an important policy which had at its core racial segregation between black and white people.