question_answer

The equation \[a{{x}^{2}}+b{{y}^{2}}+2hxy+2gx+2fy+c=0\] will represent a circle, if  [MNR 1979; MP PET 1988; RPET 1997, 2003]

A)            \[a=b=0\] and \[c=0\]           

B)            \[f=g\] and \[h=0\]

C)            \[a=b\ne 0\] and \[h=0\]        

D)            \[f=g\] and \[c=0\]