The bars represent a spread of likeliness to get the answer right based on how you score on the LSAT. For this question, 135 is expected to get the right answer 25% of the time, 158 is right 50% of the time, and 180 75% of the time.

For your first point, E says small families specifically, which means you don't have to make the assumptions about family size that made A wrong. The day care point is interesting and I think it does require you to make the assumptions that the day cares are both populated and have germs, but these are both very reasonable. As for the last part though, the answer specifies before age 1, so even if it was 1 second later they would no longer be an infant. Good luck and hope this helps!

From an admin response on the 7sage forum: "The target time for LR is the median duration for students who got the question correct. For LG/RC, it's the median time for students who got -2 or better on the game/passage. The target time for each question is different. Some might be more than what you actually spent and some less."