Nice! And good to see you studying for the test, really not that difficult to pass and well worth the effort.
Every antenna mount is a compromise. So you just have to decide which things you can live with, and which you can live without, then make your decision. will offer up a brief opinion...
Front/rear bumper: positives is it's easy to do, decent range, not great. downside it's in your way, a lot, even in your field of vision. On the plus side, it's lower so protected by the vehicle from trees, able to get into garages, etc. Downside is the vehicle's in the way of your propogation.
Top of the roof: hands down best ground plane there is, best send/receive. downside it's in the way for pretty much anything else, like loaded roof racks, RTT's, etc. Also trees and rocks will abuse it, even break it, even parking garages and drive thru windows.
rear hatch, side of rear hatch: not as good send/receive as top of the roof, with almost all of the same downsides for clearance. Positives is it's easy to install, and move. But IMO it's in the way. You are always negotiating the antenna every time you open the back door, and that puts wear on both the antenna and cable, you'll get tired of bonking into it. Even worse on a hatch mount for 60/80/100/200's where the hatch flips up, now your antenna smacks into the stuff on your roof rack. Did I mention I don't like the rear hatch for antennas...
Front fender mount: Pretty easy to install, decent send/receive, and out of the way most of the time. Able to leave the antenna on and still get into garages, occasionally have to remove it to do maintenance. Downside generally not beefy to support a full wave 2m or larger HF antenna, can be in field of view if on the driver's side.