Answer:
option a and c both are correct
Explanation:
please mark me as brainliest
C is your answer. Because if you add two of them together you get a compound.
John Dalton
Although the concept of the atom dates back to the ideas of Democritus, the English meteorologist and chemist John Dalton formulated the first modern description of it as the fundamental building block of chemical structures.
I don't know because your question is very unclear