I just spent a solid whack of time in the mountains , six full days out of the last eight hiking in Garibaldi Provincial Park . And I could n't be happier still feeling the burn in my legs . It started last Sunday with a 30-plus kilometre day trip into the Diamond Head area .

Question: What is causing the narrator to be presently so exhausted ?
Answer: None of the above choices .They did not sleep the night before .They just went off on an excursion .They could n't get to bed .