The correct answer is C. It was based on the thoughts of an early philosopher.
Step-by-step explanation:
An atom is a basic and smallest unit that composes matter and that determine the properties of elements. Regarding the development of ideas related to atoms these did not begin in science but in philosophy; indeed the first person that proposed matter or elements were composed of certain smaller units was the philosophers Leucippus and his pupil Democritus in Ancient Greece, who stated atoms were eternal, infinite and defined the qualities of an object, idea that was supported by other Greek philosophers. But it was not until 16th and 17th centuries after the Middle Ages that the term re-emerged and until the 19th century it was officially proposed and there were experiments by scientists that later became a theory. Therefore, the development of the earliest idea about attoms differs from later work of scientists is that the earliest idea was based on the thoughts of an early philosopher.