An American manufacturer of racing bikes reported a 1996 second-quarter gross income of $18 million, compared with $11.5 million in the second quarter of 1995. This increase was realized despite a drop in U.S. sales of racing bikes in 1996 compared with i995, which was partly attributable to the unusually high sales in 1995 as a result of the unprecedented success of an American cyclist in a high-profile international race. Which of the following, if true, would contribute most to an explanation of the increase in the manufacturer’s gross income in 19967 ？（）
A. Foreign manufacturers of racing bikes announced increased sales of their products in Europe in 1996 compared with 1995.
B. In the first quarter of 1996, the American cyclist who won the high-profile international race in 1995 announced that he was switching to the racing bike made by the manufacturer in question.
C. In the first quarter of 1995, the manufacturer in question first began selling its top-of-the-line "Titanium Extreme" model.
D. In the second quarter of 1996, the manufacturer announced that it would begin production of skateboarding equipment in the following quarter.
E. Intense competition in the racing bike market forced a competitor of the manufacturer to go out of business in the fourth quarter of 1996.