Official Solution:If \(m\) and \(n\) are positive integers, is \(m\) even? (1) \(\frac{m}{n}\) is an odd integer.
The above implies that \(m=n*\text{odd}\). Now, if \(n\) is odd, then \(m\) is also odd. However, if \(n\) is even, then \(m\) is also even. Not sufficient.
(2) \(m+n\) is an even integer.
The above implies that either both \(m\) and \(n\) are odd or both \(m\) and \(n\) are even. Not sufficient.
(1)+(2) Still the same two cases are possible: either both \(m\) and \(n\) are odd (for example \(m=3\) and \(n=1\)) or both \(m\) and \(n\) are even (for example \(m=2\) and \(n=2\)). Not sufficient.
Answer: E