I think it is failing at reading comprehension because it is putting too much emphasis on 3 events (A, B and C) ordered. If we rewrite the question to make it

I think it is failing at reading comprehension because it is putting too much emphasis on 3 events (A, B and C) ordered. If we rewrite the question to make it very simple to interpret it gets the logic correct: Imagine a set of 3 ordered events (A, C and B) with unique timestamps each. The ordering is A, C, B. What is a valid bound for Event B's timestamp? > A valid bound for Event B's timestamp would be a range of values that fall between the timestamp of Event A and the timestamp of Event C. For example, if the timestamp of Event A is 5:00 PM and the timestamp of Event C is 6:00 PM, a valid bound for Event B's timestamp could be 5:15 PM to 5:45 PM.