名词解释：Pitting edema

Pitting edema of the face， limbs or over the entire body， heaviness， distension， dullness on percussion， scanty urine， enlarged tongue mostly refers to （ ）syndrome。 A: Phlegm B: Dampness C: Water retention D: Body fluid deficiency

When fuel enters the crankcase of a diesel engine, it （） A: dilutes the lube oil and reduces its viscosity B: forms sulfuric acid in the lube oil C: causes pitting and failure of the bearings D: causes sludge deposits on valve stem