Point of contact : (8,16) Equation of tangent ⇒y=x+8∴ Slope (m)=1 i.e. Matching with (i) of column 2 my=m2x+ay=x+8 Hence, m=1 and a=8 Matching with (P) of column 3:(m2a,m2a)⇒(18,12×8)=(8,16) Matching with column 1 1) x2+y2−a2=0⇒82+162−82=0 2) x2+a2y2−a2=0⇒82+(82×162)−82=0 3) y2=4ax⇒162−4(8)(8)=0 Hence, equation of curve ⇒y2=4ax Point of contact: (m2a,m2a) Tangent ⇒my=m2x+a Hence, option D is correct.