Find the unit digit of \(3^{57}\).
Answer: B
The power cycle of the unit digit for 3 is (3, 9, 7, 1), with a length of 4. We find the remainder of the power \(57\) when divided by 4. \(57 \div 4 = 14\) with a remainder of 1. The required unit digit is the 1st in the cycle, which is 3.