Pharmaceutical companies spend more than ever on research and development; yet the number of new drugs patented each year has dropped since 1963. At the same time, profits—at constant 1963 dollars—for the industry as a whole have been steadily increasing.

Which of the following, if true, is the single factor most likely to explain, at least in part, the three trends mentioned above for money spent, drugs patented, and profits made?

A:Government regulations concerning testing requirements for novel drugs have become steadily more stringent.

B:Research competition among pharmaceutical companies has steadily intensified as a result of a general narrowing of research targets to drugs for which there is a large market.

C:Many pharmaceutical companies have entered into collaborative projects with leading universities, while others have hired faculty members away from universities by offering very generous salaries.

D:The number of cases in which one company's researchers duplicated work done by another company's researchers has steadily grown.

E:The advertising budgets of the major pharmaceutical companies have grown at a higher rate than their profits have.