The correct answer is C) water. If a person gets battery acid in their eye, the first and most important step is to immediately flush the eye with large amounts of clean, running water. This helps dilute and wash away the acid, preventing further damage to the eye. The water helps neutralize the acidic pH and prevents the acid from causing chemical burns to the delicate eye tissues. The other options are incorrect because boric acid and ammonia solutions can also cause irritation and damage to the eye, while baking soda, while a weak base, may not be as effective as simply using large volumes of clean water to flush the eye.