Beverage company representative: The plastic rings that hold six-packs of beverage cans together pose a threat to wild animals, which often become entangled in the discarded rings and suffocate as a result. Following our lead, all beverage companies will soon use only those rings consisting of a new plastic that disintegrates after only three days' exposure to sunlight. Once we all complete the switchover from the old to the new plastic rings, therefore, the threat of suffocation that plastic rings pose to wild animals will be eliminated.

Which one of the following, if true, most seriously weakens the representative's argument?

A. The switchover to the new plastic rings will take at least two more years to complete.
B. After the beverage companies have switched over to the new plastic rings, a substantial number of the old plastic rings will persist in most aquatic and woodland environments.
C. The new plastic rings are slightly less expensive than the old rings.
D. The new plastic rings rarely disintegrate during shipping of beverage six-packs because most trucks that transport canned beverages protect their cargo from sunlight.
E. The new plastic rings disintegrate into substances that are harmful to aquatic animals when ingested in substantial quantities by them.

Unless I'm missing something, B.

A. The switchover to the new plastic rings will take at least two more years to complete. - doesn't matter. Representative says the threat will reduce only after the switchover is complete. OUT
B. After the beverage companies have switched over to the new plastic rings, a substantial number of the old plastic rings will persist in most aquatic and woodland environments. - Yes. Thus, threat will not decrease.
C. The new plastic rings are slightly less expensive than the old rings. - Irrelevant. OUT
D. The new plastic rings rarely disintegrate during shipping of beverage six-packs because most trucks that transport canned beverages protect their cargo from sunlight. - Irrelevant. Disintegration during transportation does not matter here. OUT.
E. The new plastic rings disintegrate into substances that are harmful to aquatic animals when ingested in substantial quantities by them. - Irrelevant.We are only worried about the threat of suffocation. OUT

yep...B.
_________________

The path is long, but self-surrender makes it short;
the way is difficult, but perfect trust makes it easy.

Sure, sunlight can penetrate only so far into water (hence the loss of color with greater depths) and a canopy of leaves and branches could block out sunlight altogether in a dense forest.

well-done everyone~ OA is B