Two identical isolated metal spheres carry charges +2μC and −1μC respectively. They are suddenly brought into contact and then separated. Which statement is correct about the total charge of the system before and after contact?
a) Total charge becomes 0 after contact because the opposite charges neutralise.
b) Total charge is +1μC before contact but falls to +0.5μC after equal sharing.
c) Total charge remains +1μC both before and after contact.
d) Total charge is taken as +3μC both before and after contact because magnitudes add up.