Atomic mass is determined by the number of protons plus the number of a. electrons b. neutrons c. charges d. atoms

The correct answer is option B that is neutrons.  

The atomic mass refers to the mass of an atom of a chemical element articulated in atomic mass units. It is about the same to the number of protons and neutrons in the atom (the mass number) or to the average number permitting for the relative abundances of distinct isotopes.  

The atomic mass of a single atom of an element is determined by supplementing the mass of protons and neutrons.  

just finished the test, the answer is d, greg is the least cost-effective because he charges the most for the project