After Archimedes Suddenly Realized the Solution to His Problem of Whether

After Archimedes suddenly realized the solution to his problem of whether the king had been cheated,he tested this solution by placing the amount of gold given to the goldsmith in a tub of water and marked the water level and removed the gold.He then placed the crown in the water.If the goldsmith had cheated the king,the water level would be different than the water level marked for the pure gold.At this point,Archimedes was in which stage of creative thought?

A) preparation
B) incubation
C) illumination
D) verification