The correct answer is B) premature wear of both the pulley end motor shaft bearing and the pulley end compressor crankshaft main bearing due to overloading. Excessively tight drive belts between a motor and a refrigeration compressor pulley will cause increased tension and load on both the motor shaft bearing and the compressor crankshaft main bearing. This excessive load will lead to premature wear and failure of both bearings, as the system is being overworked beyond its design specifications. The other answer choices are incorrect because: A) only the motor shaft bearing would experience premature wear, not the compressor bearing; C) only the motor shaft bearing would experience premature wear, not the compressor bearing; and D) both motor and compressor bearings would experience premature wear due to belt slippage, not overloading.