【名词&注释】
原材料(raw material)、冷却水(cooling water)、船舶动力装置(marine power plant)、增压器涡轮(turbine wheel)
[单选题]If the sump()were to rise this would indicate water leakage into the oil an d an investigation into the cause must be made.
A. temperature
B. viscosity
C. lever
D. level