What is the atomic mass, in atomic mass units (amu), of 12vC?

The atomic mass of 12vC, which stands for the most common isotope of carbon with an atomic mass number of 12, is precisely 12.00000000 amu. This value reflects the total number of protons and neutrons in the nucleus of the carbon atom, specifically 6 protons and 6 neutrons.

This number is a standardized value for the isotope known as carbon-12, and it is used as a reference point for measuring atomic masses of other elements and isotopes. The decision to assign a value of exactly 12.00000000 amu to carbon-12 is due to its definition in the atomic mass unit system, making it a fundamental standard in chemistry and physics.

The other options represent atomic mass values that are not associated with carbon-12. These values are indicative of heavier isotopes of carbon or entirely different elements, which do not apply in this context. Thus, option A accurately captures the atomic mass of the most prevalent isotope of carbon.