Final answer:
The sentence that best concludes the paragraph about Tabitha and the challenging waves is the one that describes the waves as the most monstrous she has ever seen.
Step-by-step explanation:
After reading the paragraph, which describes Tabitha’s contemplation as she observes the challenging waves before a surfing attempt, the best sentence to finish the paragraph among the provided options is:
She had been surfing for years, but these waves were the most monstrous she had ever seen.
This sentence best aligns with the preceding description of the towering green waves and their comparison to an angry sea creature, highlighting the scale and intimidating nature of the waves.