Until 1984 only aspirin and acetaminophen shared the lucrative nonprescription pain-reliever market. In 1984, however, ibuprofen was expected to account for fifteen percent of all nonprescription pain-reliever sales. On that basis business experts predicted for 1984 a corresponding fifteen percent decrease in the combined sales of aspirin and acetaminophen.

The prediction mentioned in the last sentence above was based on which of the following assumptions?
A.Most consumers would prefer ibuprofen to both aspirin and acetaminophen.
B.Aspirin, acetaminophen, and ibuprofen all relieve headache pain and muscular aches, but aspirin and ibuprofen can also cause stomach irritation.
C.Before 1984 ibuprofen was available only as a prescription medicine.
D.The companies that manufacture and sell aspirin and acetaminophen would not also manufacture and sell ibuprofen.
E.The introduction of ibuprofen would not increase total sales of nonprescription pain relievers.