59.
The answer is: B
Explanation
The correct option is B: six months of attaining majority.
According to Section 30(5) of the Indian Partnership Act, a minor who has been admitted to the benefits of the partnership has to decide whether to become a partner or not within six months of his attaining majority, or of his obtaining knowledge that he had been admitted to the benefits of partnership, whichever date is later. If he fails to give a public notice of his choice, he shall become a partner in the firm by default.
This provision is meant to protect the rights and liabilities of the minor as well as the other partners in the firm.