The solution of the differential equation \(\left( {x\sin \left( {\frac{y}{x}} \right)} \right)dy - \left( {y\sin \left( {\frac{y}{x}} \right) - x} \right)dx = 0\) is:

• A. \(\cos \left( {\frac{y}{x}} \right) - \log x = c\)
• B. \(\sin \left( {\frac{y}{x}} \right) = 0\)
• C. \(\cos \left( {\frac{y}{x}} \right) = 0\)
• D. \(\sin \left( {\frac{y}{x}} \right) - \log x = c\)