passage oneRacket, din clamor, noise, whatever you want to call it,unwanted sound is America’s most widespread nuisance. Butnoise is more than just a nuisance. It constitutes a real andpresent danger to people’s health. Day and night, at home, atwork, and at play, noise can produce serious physical andpsychological stress. No one is immune to this stress. Thoughwe seem to adjust to noise by ignoring it, the ear, in fact, nevercloses and the body still responds—sometimes with extremetension, as to a strange sound in the night. The annoyance we feel when faced with noise is the most common outward symptom of thestress building up inside us. Indeed, because irritability is so apparent, legislators have madepublic annoyance the basis of many noise abatement programs. The more subtle and moreserious health hazards associated with stress caused by noise traditionally have been given muchless attention. Nevertheless, when we are annoyed or made irritable by noise, we should considerthese symptoms fair warning that other thing may be happening to us, some of which may bedamaging to our health. Of many health hazards to noise, hearing loss is the most clearly observable and measurable byhealth professionals. The other hazards are harder to pin down. For many of us, there may be arisk that exposure to the stress of noise increases susceptibility to disease and infection. The moresusceptible among us may experience noise as a complicating factor in heart problems and otherdiseases. Noise that causes annoyance and irritability in health persons may have seriousconsequences for these already ill in mind or body. Noise affects us throughout our lives. For example, there are indications of effects on the unbornchild when mothers are exposed to industrial and environmental noise. During infancy andchildhood, youngsters exposed to high noise levels may have trouble falling asleep and obtainingnecessary amounts of rest. Why, then, is there not greater alarm about these dangers Perhaps it is because the link betweennoise and many disabilities or diseases has not yet been conclusively demonstrated. Perhaps it isbecause we tend to dismiss annoyance as a price to pay for living in the modern world. It may alsobe because we still think of hearing loss as only an occupational hazard. In Paragraph 1, the phrase "immune to" are used to mean ___.

A. unaffected by
B. hurt by
C. unlikely to be seen by
D. unknown by