Final answer:
Opposite charges of equal magnitude cancel each other out, producing a net charge of zero. Thus, for the data given, sets a) +1 Coulomb and -1 Coulomb and b) +2 Coulombs and -2 Coulombs present cancelled charges. Same-sign charges, as in sets c) and d), do not cancel each other.
Step-by-step explanation:
In the context of electrical charges, when we say that opposite charges 'cancel', it means that when you combine a positive and negative charge of equal magnitude, the total charge results in zero. This concept is derived from the law of conservation of charge, which states that the net charge in an isolated system will always remain constant.
Thus according to this law and the phenomenon of 'charge cancellation', the sets of data that show cancelled charges would be: a) +1 Coulomb and -1 Coulomb, and b) +2 Coulombs and -2 Coulombs. These pairs of charges, being equal in magnitude and opposite in sign, will cancel out to give a total charge of zero.
In contrast, options c) +3 Coulombs and +3 Coulombs, and d) -4 Coulombs and -4 Coulombs, don't result in total charge cancellation, as they involve charges of the same sign.
Learn more about Charge Cancellation