In a car accident, air bags greatly reduce the risk of serious injury. However, statistics show that cars without air bags are less likely to be involved in accidents than are cars with air bags. Thus, cars with air bags are no safer than cars without air bags.
The argument is most vulnerable to criticism on the grounds that it
(A) assumes, without providing justification, that
any car with air bags will probably become involved in an accident - WRONG. 2nd best choice here. Claiming "any" is a bit going ballistic which is not good.
(B) denies the possibility that cars without air bags have
other safety features that reduce the risk of serious injury at least as much as do air bags - WRONG. Other features don't matter. Also, its not about cars without air bags but with air bags.
(C) overlooks the possibility that
some accidents involve both cars with air bags and cars without air bags - WRONG. Exceptions!!! Also, doesn't impacts the conclusion.
(D) assumes, without providing justification, that the
likelihood of an accident’s occurring should weigh at least as heavily as the seriousness of any resulting injury in estimates of relative safety - CORRECT. Rightly so why air bags are given in a car. Accidents may happen for reasons beyond control of driver/passengers of car with air bags but it is these bags that in the end provide safety. Thus, at crucial juncture the bags may give necessary safety.
(E) takes for granted that all accidents would cause air bags to be
deployed - WRONG. In a way goes against what we are looking for as in it supports cars with air bags.
Answer D.