Answer: The right answer is the C) How loud she yells.
Explanation: Just to elaborate a little on the answer, it can be added that by comparing the mother's loud tone of voice to the sound of the ocean, the poet is using a figure of speech known as a simile, since he is saying that the mother sounded like, or similar to, a rough ocean when she yelled at her daughter. By doing so, he is emphasizing the mother's words, and ultimately their meaning - the little local girl was not supposed to get near the beach that was reserved for the wealthy tourists.