Answer:
C
Explanation:
Because D ask "They have a negative charge" yes and no, but neutrons do, Why? Well because the neutron has a negative charge both in its inner core and its outer edge, with a positive charge sandwiched in between to make the particle electrically neutral. Whilst B is wrong because like protons and electrons they were both measured and observed differently, just as the neutron. So that makes C the only correct answer.