The answer is: C
Explanation
The correct option is C: 280.
According to Section 112 of the Indian Evidence Act, 1872, the law presumes that if a child is born during the continuance of a valid marriage between his mother and any man, or within two hundred and eighty (280) days after its dissolution, the mother remaining unmarried, it is a conclusive proof of its legitimacy unless it can be proven that the parties to the marriage did not have any access to one another. This section is based on the principle of public morality and public policy, and it does not allow evidence to be given for the purpose of disproving the legitimacy of the child, except in the case of non-access. Therefore, if a child is born within 280 days after the dissolution of a valid marriage, it is a conclusive proof of the legitimacy of the child.