Concept:Find the derivative of sin2x with respect to cos2x.Explanation:Let y=sin2x and u=cos2x.We need dudy.Compute dxdy=dxd(sin2x)=2sinxcosx=sin2x.Compute dxdu=dxd(cos2x)=−2cosxsinx=−sin2x.Now dudy=dxdudxdy=−sin2xsin2x=−1.Thus, the derivative is −1.Answer:Option A: −1.