Please answer experts....

Dear student

By definition
1amu(atomic mass  unit ) is defined as the mass equal to one twelfth of the mass of an atom of carbon -12.
1 amu =$\frac{1}{12}\times mass of an atom of carbon ( C-12)$
Hence, 24 amu would mean 24 times one twelfth the mass of carbon atom, hence first option is correct.

Regards