OK this is a tough call
100baseFX will do 2km over 62.5 or 50 nm multimode fiber, so it is an obvious choice now.
but if you need gigabit in the future, multimode (at 50nm ) can do 550 meters not nearly long enough, so you may need Single mode in the future. Single mode 100 meg gear is rare though.
I tried to remain child-like, all I acheived was childish.