First off, what country/nation is the question based on?
I will go ahead and give you a generalized answer that could apply for any country/nation:
In the past, it was important for the military to guard is gold reserves and mines so that other "enemies" couldn't just go walk in an steal their gold from their mines or reserves. And pretty much the same applies with trade routes, and also so people couldn't go hijacking their trade routes and steal goods from the people travelling the route.
Probably he or she meant like how he ran his government or how he basically ruled his country.
D. a place for socializing
The Roman baths were very important in Roman culture because these public baths were the most important places for socialisation of people from different classes and backgrounds. The larger ancient Roman baths were even accompanied by villas, town houses, libraries and forts.
I don’t know I just had to answer a question sorry