381 A centrifugal pump vibrates excessively during operation. Upon disassembling the pump it is found that the impeller is out of balance. Without an available spare, you should __________.

A. drill holes through the heavy side of the impeller until it balances
B. weld counterweights to the light side of the impeller
C. remove metal from the heavy side by machining in a lathe
D. acid wash and scrape the heavy side until it balances