In 1970, Spencer Silver Was Trying to Formulate a Strong

In 1970, Spencer Silver was trying to formulate a strong adhesive for the 3M Company, and one of his failed attempts resulted in an extremely weak adhesive. Four years later, frustrated by how often his markers fell out of his church hymnal, Arthur Fry coated them with Silver's adhesive. The markers stayed in place but could be peeled out of the book without damaging the pages. Post-it Notes are now one of the top five-selling office products in the United States. Fry's novel approach is a good example of

A) functional fixedness.
B) divergent thinking.
C) the confirmation bias.
D) the availability heuristic.
E) a mental set.