The given passage is a dialogue between father and a son. Sanju had lost his lucky bat and his father is trying to restore his confidence.
With a proverb, Sanju's father tries to explain the truth behind his success.
The tense of a proverb shall remain unchanged as the truth can never change.
Therefore, the proverb itself shall fill in the given blank.
The completed sentence shall be,
When Sanju failed to understand, his father explained that it is the batsman and not the bat that matters and that it was confidence that one needed.Thus option B is the correct answer.
Options A,C,D are incorrect as they are not in the correct tense.