Given below are two statements: one is labelled as Assertion \(A\) and the other is labelled as Reason \(R\). Assertion \(A\) : Body \('P'\) having mass \(M\) moving with speed \('u'\) has head-on collision elastically with another body \('Q'\) having mass \('m'\) initially at rest. If \(m< < M,\) body \('Q'\) will have a maximum speed equal to \('2u'\) after collision. Reason \(R\) : During elastic collision, the momentum and kinetic energy are both conserved. In the light of the above statements, choose the most appropriate answer from the options given below:

1. A \(A\) is not correct but \(R\) is correct.
2. B Both \(A\) and \(R\) are correct but \(R\) is \(NOT\) the correct explanation of \(A\).
3. C Both \(A\) and \(R\) are correct and \(R\) is the correct explanation of \(A\).
4. D \(A\) is correct but \(R\) is not correct.