Statement I provides a more complex relationship :
\(w = \frac{1}{2}m - 3\)
This relationship alone does not directly give a simple ratio because it involves subtraction, making it impossible to immediately find a proportional ratio.
Statement II provides a clear, direct proportion :
\(w = \frac {2}{5}m\)
which immediately leads to a ratio of \(m:w = 5:2\). Hence, Statement II is sufficient on its own.
So, the correct option is (B): If statement II by itself is sufficient to answer the question, but statement I by itself is not.