Grand assumptions would be exaggerations
For me the poet wants to be in a place that is near the wind and the sea and in which he can access to ancient truths and beauties. His desire is to live in the eternally changing powers with the ancient God of the seas and rivers. So, this God is always changing forms and that makes the discovery of the truth more difficult. Another God that the author invokes is Triton which is another sea God and use his powers to calm waters.
The best answer would be Letter B - to entertain.
The author merely would like to provide amusement to the readers at his expense. It certainly does not persuade, explain, nor inform anything since it states - <span>But why bother with the descriptions; you’ve probably already grasped the idea!</span> - which could be taken as a witticism.