Pretty self-explanatory, what is the longest time you've been away from school? This includes being sick, family vacations, and school disasters. (Hurricanes, tornadoes, etc.) This does not include summer vacation unless it is before or after the time you were away. (i.e. you were sick for the first 3 weeks of school)
For me, I've been away for 5 months because of Epstein-Barr.