You will be given a definition of a task first, then some input of the task.
In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".

[header] How to board a small boat [title] Prefer boarding across a solid platform if possible. [step] Always board as near to the middle of the boat as possible. [title] Hold on. <sep> (A) [step] Either stand on the deck or simply lie on the surface. This simple trick can help if you have to shift your weight onto two legs at once. (B) [step] Don't let go of the front rail. This would be easily knocked over and you could potentially drive yourself to the bottom. (C) [step] If you are on the edge or side, lock your fingers, making sure your fingers don't slip out or get tangled in the rope. Hold onto the bar at either end with your thumb and forefingers. (D) [step] If you are crossing using a platform, hold on to the rails provided. If you are getting onto the boat off a jetty or via wading, hold on to the boat itself.
Output:
D