单选题：Every year more than half a million American kids have drain

Every year more than half a million American kids have drainage (排泄 ) tubes surgically implanted in their ears to combat persistent infections. The procedure, known as tympanostomy, may not be as 67 as the tonsillectomy was in the 1940s, but it now 68 as the nation's leading childhood 69 and a new study suggests it's being vastly overused. In 70 more than 6,000 scheduled ear tube operations, a team of experts 71 by Harvard pediatrician Lawrence Kleinman found that fewer than half were clearly justified. "Each year", the researchers write in the
current Journal of the American Medical Association (JAMA), "several hundred thousand children in the United States may be 72 tympanostomy tubes that offer them no demonstrated 73 ...and may place them at increased 74 ."
Tube placement isn't a 75 risky procedure, but it costs $1,000 to $1,500 and sometimes scars the eardrum, causing a partial loss of 76 . Studies show that the
benefits are most likely to 77 the risks ifa child's middle ear has produced sticky fluid 78 more than four months despite treatment 79 antibiotics. For less virulent infections, drug treatment is Usually a(n) 80 , safer alternative (though drugs, too, can be overused). In the new JAMA study, Kleinman's team reviewed the medical charts of 6,429 kids, all under 16, 81 doctors had recommended the procedure. Even making "generous assumptions" about the likely 82 , the researchers found that a quarter of the proposed operations were 83 , since less invasive alternatives were available, 84 another third were as likely to harm the recipients as help them. Parents needn't 85 about ear tubes that are already in place. Once 86 implanted, the tiny devices provide drainage for six months to a year, then come out by reducing health costs by hundreds of millions of dollars every year.根据以上短文，回答题请在（67）处填上最佳答案。 A． rare
B． common
C． general
D． abnormal