Compound words are words formed by combining two words together into a new word itself; one which often has its own separate meaning. In this case, the word 'candlelight' refers to the light emanating from a candle; thus the correct answer is Option C). All the remaining options do not appropriately fit into the rest of the sentence. A clue here is about the electricity being cut off - forcing the speakers of the sentence to use light from smaller sources, such as candles.