Answer:
A. It presents the subject of the paper
Explanation:
A thesis statement focuses your ideas into one or two sentences. It should present the topic of your paper and also make a comment about your position in relation to the topic. Your thesis statement should tell your reader what the paper is about and also help guide your writing and keep your argument focused.
Large is an Adjective
Fish is a Noun
Swim is a Verb
Swiftly is an Adverb
In is a preposition
The is a determiner
Sea is a noun.
I hope this helps since you didn't say which word is italicized.