The number of protons, neutrons, and electrons in respectively are:
175, 104, and 71
71, 104 and 71
104, 71 and 71
71, 71 and 104
The atomic number is equal to the number of protons or electrons. Thus, the number of protons and electrons are 71. Now, the atomic mass = number of protons + number of neutrons.
Thus, number of neutrons = 175 - 71 = 104
Therefore, Option(2) is correct.