I think the correct answer is the first one, "The men have enough oxygen in their bottles so they are able to complete their climb to the summit of Mt. Everest." It could be C.
Hillary and Tenzing were a little behind collecting partially used bottles of air left behind, so not the second. The last one is kind of petty, but there was some concern about this because only one group of climbers was allowed on the Everest per year, and the next years were already booked.
