The correct conjugation is 'il boit' - the third-person singular form of the verb 'boire' (to drink). The verb 'boire' is irregular in French: je bois, tu bois, il/elle boit, nous buvons, vous buvez, ils/elles boivent. 'Elles boit' is incorrect (should be 'elles boivent'), 'tu boit' is wrong (should be 'tu bois'), and 'je vais' means 'I go' (different verb).