In the Research Surrounding the Launch of New Coke in the 1980s

In the research surrounding the launch of New Coke in the 1980s, what key mistake was NOT made?

A) overreliance on research findings
B) overemphasis on initial taste test findings
C) failure to make usage tests
D) failure to take into account research that found sweeter things tested higher on initial taste tests
E) providing the product for use for two to three weeks