Some species of Arctic birds are threatened by recent sharp increases in the population of snow geese, which breed in the Arctic and are displacing birds of less vigorous species.  Although snow geese are a popular quarry for hunters in the southern regions where they winter, the hunting season ends if and when hunting has reduced the population by five percent, according to official estimates.  Clearly, dropping this restriction would allow the other species to recover.

Which of the following, if true, most seriously undermines the argument?

我仔细研究了一下，看来这道题所说的restriction是指 hunting season 的时间限制。

所以说题里面要取消的限制 也是指这个 hunting season 的time line.

如果这样理解，那b选项，因为5%总是先达到，所以取消这个时间限制也没用

我之前一直把这个restriction理解成了 5%的数目限制。

It has been many years since the restriction led to the hunting season for snow geese being

closed earlier than the scheduled date.

The restriction has led to the hunting season being closed earlier than the schedule date, the

ecologic balance of the nature has well prepared many of the weak species like Arctic birds for the

sharp increase of its predator. This evidence also tells that the original restriction has already

allowed the prosperity of snow geese, since the schedule date is shorten by the hunting season. The

long persistence of both the restriction and prosperity of snow geese probably has done nothing to

Arctic birds.

The ecologic balance is the center issue in the analysis. The sharp increase of snow geese

population may well due to a proportional increase in pray such as Arctic birds. Consequently we do

not need to worry about the threatening to Arctic birds. Since the restriction, protecting the snow

geese with 5% restriction while cause the hunting season closed earlier for many years, the ecology

is well balanced, therefore it is not necessary to drop this restriction to allow the other species

to recover.

D. As their population has increased, snow geese have recolonized wintering grounds that they had

not used for several seasons.

This has gone far beyond the argument of dropping the restriction; If they colonize to other winter

ground the threats to our local Arctic bird would decrease, therefore there is less necessity for us

to drop the restriction.