Final answer:
The atom with the smallest number of neutrons is A) carbon-12 (¹²C), which contains 6 neutrons.
Step-by-step explanation:
The atom with the smallest number of neutrons is carbon-12 (¹²C). It contains 6 neutrons.
Neutrons are particles found in the nucleus of an atom and their number can vary among different isotopes of an element.
In this case, carbon-12 has the fewest neutrons among the options given.