IMPECCABLEImpeccable = in accordance with the highest standards; fault
Right Answer is: C
Impeccable = in accordance with the highest standards; faultless.
Perfect = having all the required or desirable elements, qualities, or characteristics; as good as it is possible to be.
Capricious = changing mood or behaviour suddenly and unexpectedly
Vicious = cruel or violent; immoral
The word “faultless” is the correct synonym of the given word.