The given answer is correct because it states that all the statements are correct. The statements provided in the question mention that saliva is produced by the parotid, submandibular, and sublingual glands, and it is secreted by the mucous, serous, and mixed acini of the salivary glands, tongue, and oral cavity. Additionally, saliva contains water, mucus, amylase, and lgA. Therefore, all the statements mentioned in the question are accurate.