Answer:
d. hiking up a mountain trail.
Step-by-step explanation:
Endurance refers to the time from the start to end, when you stop because you cannot keep going. So, having physical endurance will make you able to hike up a mountain, because this activity is one of the most physical demanding. A person can be the best weight lifter at the gym, but if he doesn't train endurance, that person won't be able to hike a mountain.
On the other hand, the other option that we could think is "raising a 100-pound barbell on time", but this activity requires strength not endurance.