Final answer:
The correct answer is c. Archimedes, who devised a method to test the purity of gold by using water displacement, leading to the formulation of Archimedes' principle.
Step-by-step explanation:
The Greek philosopher known for testing the purity of the gold in the King's crown using water was Archimedes. This historically significant event led to one of the most famous principles in physics—Archimedes' principle. While sitting in a public bath, Archimedes noticed the displacement of water and realized that he could use this concept to determine the crown's density, thereby verifying if it was made of pure gold or mixed with other metals. In his excitement, he is said to have run through the streets shouting "Eureka!", which means "I have found it" in Greek.
Archimedes' principle deals with the buoyancy and displacement experienced by an object submerged in a fluid, which depends on the density of the object relative to the fluid. This principle is an essential part of physics as it helps understand why objects float or sink, and it is integral in the fields of engineering and fluid mechanics.