Explanation:

Boric acid (H$_3$BO$_3$) is commonly used as a mild antiseptic and astringent for eye washes. Its weak acidic nature makes it safe for ophthalmic use, helping to soothe irritation and cleanse the eyes. Option C, Boric acid, is the correct answer. Option A, Oxalic acid, is a strong organic acid and is highly corrosive, making it unsuitable and dangerous for eye contact. Option B, Nitric acid, is a very strong mineral acid and is extremely corrosive, causing severe burns. Option D, Acetic acid, while a weak acid (like in vinegar), is still too irritating and concentrated for direct use as an eye wash, although dilute solutions are used in other medical contexts.