If the bisectors of the angles between the pairs of lines given by the equation \[a{{x}^{2}}+2hxy+b{{y}^{2}}=0\] and \[a{{x}^{2}}+2hxy+b{{y}^{2}}+\lambda ({{x}^{2}}+{{y}^{2}})=0\] be coincident, then \[\lambda =\]

• A.            a    
• B.            b
• C.            \[h\]       
• D.            Any real number