answer is in attachments, Have a look.
During the Vietnam war, the country is separated hawks and doves. It is because we couldn't defend against Vietnam.
Imperialism is the intention of one country to rule over another country: for example Great Britain wanted to gain control over India - this is an example of imperialism.
For this land is definitely needed : without a land, there is no "other" land to take over.
I would say that the other necessary aspect is people: the ruling country will need some local population to rule the country, if not only to translate and help them communicate with the local population.
Answer:
correct answer is option a and d