A \( x^2 + y^2 - 10x \pm \sqrt{21}y + 21 = 0 \)
B \( x^2 + y^2 - 10x \pm 2\sqrt{21}y + 21 = 0 \)
C \( x^2 + y^2 - 10x + 2\sqrt{21}y \pm 21 = 0 \)
D \( x^2 + y^2 - 10x \pm \sqrt{21}y + \sqrt{21} = 0 \)
E \( x^2 + y^2 - 10x \pm \sqrt{21}y - \sqrt{21} = 0 \)