I think it is the first one.

No, it's B.

Explanation:

It is a chemical reaction, but the reason for the lack of change in mass is not because atoms rearrange to form new substances. It's because atoms generally don't lose mass during a chemical reaction, because mass cannot be created or destroyed.

it is actually e

because even tho the old atoms turned into new atoms they had the same mass still

hope this helps!

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements