The correct answer is option C, Scientific theories are often modified , but they are not usually discarded
Democritius claimed that atom is made of simple parts (400 BC)
Joseph Thompson in 1897, discovered electrons. He didn't violated the facts of Democritius but just strengthened the facts with further discovery.
While in the next stage Neil's Bohr, Further strengthened the fact of of Thompson by clearly defining the placement of electron and proton.
