Final answer
The extracts do not explicitly mention anyone offering Ari a swimming lesson, nor do they reference a character named Ari in the context of swimming or receiving a lesson.
Step-by-step explanation:
The character Ari receives swimming lessons or guidance from different individuals in the given passages. In the first passage, Ari mentions going to the Crystal Baths where they swim. However, Ari admits they can only swim with the support of someone holding their chin up.
In the second passage, the question about swimming a mile is asked, but it doesn't specify who asks the question.
In the fourth passage, a character in a pink bathing suit is mentioned, but it doesn't state that they offer swimming lessons to Ari. The last passage talks about swimming after a boat swamps, but it also doesn't directly answer the question of who offers Ari a 'lesson' on how to swim.
Based on the given information, it is not clear who specifically offers Ari a 'lesson' on how to swim. It could be implied that Ari receives guidance or assistance from various individuals, but the text doesn't provide a clear answer to that question.