Step 1: Identify the true grammatical subject. The subject is 'the committee'. The phrase 'along with several volunteers' is a parenthetical addition, not a second subject. Phrases beginning with 'along with', 'as well as', 'in addition to' do not make the subject plural. Step 2: Determine the tense. The main verb is 'prepared'. The blank comes before it, forming the present perfect tense: has/have + past participle. Step 3: Apply SVA. 'The committee' is a collective noun — it is treated as a singular unit in standard formal English. Singular subject + present perfect → 'has prepared'. Step 4: Verify. 'The committee has prepared the hall.' This is grammatically correct. Answer: has