The isotope carbon-12 would be the result. The nucleon number 12 is the number of protons or neutrons found in the nucleus.
Carbon is an atom that has 6 ptotons within its nucleus. Many elements are composed of isotopes that have different numbers of neutrons within their nucleus. The most common isotope of carbon is the one you asked about. If you were to pick up a piece of carbon, it would be mostly carbon-12.
Carbon-14 is an useful carbon isotope. It has 6 protons as in all carbon atoms. However, this isotope also has 8 neutrons. It is radioactive with a half-life approximately 5,700 years. It can be used for dating artifacts, particularly those that were once alive.