The Endpoints of a Diameter of a Circle Are Shown $( - 1,0 )$

Multiple Choice

The endpoints of a diameter of a circle are shown. Find the center and radius of the circle.
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A) center: $( - 1,0 )$ ; radius: 4
B) center: $( 0 , - 1 )$ ; radius: $2 \sqrt { 5 }$
C) center: $( - 1,0 )$ ; radius: $2 \sqrt { 5 }$
D) center: $( 0 , - 1 )$ ; radius: 20