[" If a circle passes through the point "(a,b)&" cuts the circle "x^(2)+y^(2)=K^(2)" orthogonally,then the equation "],[" of the locus of its centre is: "],[[" (A) "2ax+2by-(a^(2)+b^(2)+k^(2))=0," (B) "2ax+2by-(a^(2)-b^(2)+k^(2))=0],[" (C) "x^(2)+y^(2)-3ax-4by+(a^(2)+b^(2)-k^(2))=0," (D) "x^(2)+y^(2)-2ax-3by+(a^(2)-b^(2)-k^(2))=0]]