Finding the y-intercepts of a circle

In the standard (x,y) coordinate plane, an equation of a circle is x² + y² = 64.  At what points does the circle intersect the y-axis?
A.)  (0,1) and (0,-1)
B.)  (0,8) and (0,-8)
C.)  (0,9) and (0,-9)
D.)  (0,10) and (0,-10)
E.)  the circle does not intersect the y-axis

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When a graph intersects the y-axis, the value of x is equal to zero.  
To find the y-intercepts, set x equal to zero.

x² + y² = 64
0² + y² = 64   {substituted 0 for x}
y² = 64   {simplified}
y = 8 or -8   {took square root of each side}

The coordinates of the y-intercepts would be
B.)  (0,8) and (0,-8)

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