Answer:
The answer would be Option A: an online almanac.
Explanation:
While both an almanac and a map would be more advantageous than using a dictionary or encyclopedia to navigate the Florida Keys, the almanac might have a slight advantage because it provides weather forecasts and tide tables and this kind of information that is often needed by navigators. However, the boat is not likely to have an internet connection or wifi signal so the sailboat crew should make sure they have a printed or downloaded copy of the almanac. A well-known example is the Reeds Nautical almanac or the Reeds Channel almanac.