The proverb, ‘Pride goes before a fall’ means: “People who are overconfident or arrogant are likely to fail’. The intent of the proverb is to advise people to be humble rather than haughty. Hence, the phrase, ‘before a fall’ given in option B completes the proverb.
The other words given in options A, C and D do not complete the proverb. Hence, these options are incorrect.