Option B is the correct answer as the English phrase ‘on purpose’ is frequently used to indicate clearly planned intention. Here, the meaning of 'deliberately' or intentionally' is coming out with the phrase 'on purpose.' Options A, C and D cannot bring out this meaning as there are no phrases such as 'in purpose,' 'out of purpose,' or 'of purpose' meaning 'intentionally' as required by the sentence. Hence, their usage would render the sentence meaningless.