The answer is B: Snorkeling.
Explanation for each option:
A. Downhill skiing - Incorrect. Downhill skiing requires a basic level of fitness due to the physical demands of controlling skis, maintaining balance, and navigating slopes.
B. Snorkeling - Correct. Snorkeling generally does not require a high level of fitness when starting out. It involves floating on the water's surface and using a snorkel to breathe, which is less physically demanding compared to the other activities listed.
C. Water skiing - Incorrect. Water skiing requires a basic level of fitness as it involves being towed by a boat, maintaining balance on skis, and using strength to hold onto the tow rope.
D. Orienteering - Incorrect. Orienteering involves navigating through terrain using a map and compass, which requires a basic level of fitness to move efficiently over various distances and terrains.
In summary, snorkeling is the activity that typically requires the least amount of initial fitness among the options provided.