Microwaves are a form of "electromagnetic" radiation; that is, they are waves of electrical and magnetic energy moving together through space. Electromagnetic radiation spans a broad spectrum from very long radio waves to very short gamma rays.
The answer is, infact, D. You were right.
Africans was exhausted all options in responding to European imperialism. Some groups tried to shut down Europeans by not trading with them and not allowing missionaries to stay with them.
I believe the answer you're looking for is <span>Sergeant, if not let me know and I will do further research.</span>