10 Gigabit Ethernet Standards

Mclewis88

So I was taking some Measure Up practice exams for Network+ prep and I came across this question about 10GBase-LR. It asked for the cable type and it's distance. I got the distance right, but I got the cable type wrong and so I got the question wrong. I consulted the three study guides and my textbooks. Two of my study guides say that all the 10 Gigabit standards are MMF while another says that only one ( I think it was LR) is SMF and the others are MMF. I'm thoroughly confused here and I just need to know which is which so I can correct my notes and get this question right incase I encoutered it again on the exam. Thank!

gehrig44

LR uses SMF only.

Oh.. and ER (if it ever comes up), also only uses SMF