单项选择题

The purpose of the wearing rings used in a centrifugal pump is to （）.

A.prevent an internal explosion in the pump when it is overheated
B.enable a visual inspection of the pump while it is running
C.insure a proper alignment of the pump coupling to the driver
D.accommodate for friction between the impeller and the easing

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船舶辅助机械

The purpose of the wearing rings used in a centrifugal pump is to （）.