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# Find the Sphere

MVCALC-AHJOLB

Which of the following surfaces is a sphere?

A

$x^2+y^2-z^2=4$

B

$\frac { x^{ 2 } }{ 4 } +\frac { y^{ 2 } }{ 4 } +z^{ 2 }=1$

C

$x^{ 2 }+y^{ 2 }+z^{ 2 }+6x-2y-8z+27=0$

D

$x^2+y^2+z^2-4x-6y-2z -2 =0$

E

$x^2+y^2=4$