An atom of tin has an atomic number of 50 and a mass number of 119. How many protons, electrons, and neutrons are found in one neutral atom of tin?
A.50 protons, 69 electrons, 50 neutrons
B.50 protons, 50 electrons, 69 neutrons
C.69 protons, 50 electrons, 69 neutrons
D.69 protons, 69 electrons, 50 neutrons