What Is the Stroop Effect

What is the Stroop effect?

A) the strategy of assuming that the number of available memories of an event indicates how common the event actually is
B) the tendency to assume that if an item is similar to members of a particular category, it is probably a member of that category itself
C) the greater ease of identifying a letter when it is part of a whole word than when it is presented by itself
D) the difficulty of naming the colors in which words are written instead of reading the words themselves