I took the wording the same as you. So i simply used a XOR gate.See I understand that, but it said that every time a switch is turned on or off, the light changed states? Wouldn't that imply the last part of the truth table (1-1) would become a 0?
Thus, I thought XOR. Anyway, I thought it was fairly ambiguously worded. We will both get 1 mark at least!