Should I get a road bike or street bike?

I am going to school at radford university in virginia. I will be bringing my truck, but student parking is about a mile away from my dorm so I want to get a bike to use it to get to close distance places and to ride to the parking lot to get my truck when I need to go further. I'm going to get one on craigslist and I have about 100 bucks to spend. I can't decide if I want a road bike or a mountain bike. The roads are somewhat hilly if that changes anything. I am an inexperienced biker btw. there is a diomondback response xe on craigslist that apears to be in good shape, and alternatively, there is a se draft for the same price.