Final answer:
Getting students ready is a gerund phrase that functions as the subject of the sentence.
Step-by-step explanation:
Getting students ready does not fall into any of the options given. It is a verb phrase that functions as the subject of the sentence. This makes it a noun phrase, specifically a gerund phrase. Gerunds are verb forms that function as nouns, and they end in -ing. In this case, the gerund phrase 'Getting students ready' serves as the subject of the sentence. So the correct answer is b) Gerund.