Correct answer choice is :
B) Experimental evidence.
Explanation:
Atomic theory is an experimental theory of the nature of matter, which says that matter is comprised of discrete units named atoms. Since atoms were observed to be separated, scientists later discovered the term primary particles to explain the uncuttable, though not strong, parts of an atom. The field of science which analyzes subatomic particles in particle physics, and it is in this field that scientists believe to determine the true basic nature of matter.
