Student or Learner
_____ his free hour 2:00 to 3:00 in the afternoon, Mr. Black has to meet with his parents and check students’ homework.
People say ‘at rush hour’ and ‘in one’s free time.’ I’m confused by this question. Would you please tell me which one is the correct answer?
You need to use "in" for that context but note that it would be better written as "In his free hour, from 2pm to 3pm, Mr Black has to ...".
I'm not sure that he is meeting with his parents. That means his own parents. It seems more likely that he is meeting some parents of the children he teaches.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.