The amplitude of a wave represented by displacement equation \[y=\frac{1}{\sqrt{a}}\sin \omega t\pm \frac{1}{\sqrt{b}}\cos \omega t\] will be [BVP 2003]

• A.            \[\frac{a+b}{ab}\]              
• B.            \[\frac{\sqrt{a}+\sqrt{b}}{ab}\]
• C.            \[\frac{\sqrt{a}\pm \sqrt{b}}{ab}\]                                
• D.            \[\sqrt{\frac{a+b}{ab}}\]