A circle is given by `x^2 + (y-1) ^2 = 1`, another circle C touches it externally and also the x-axis, then the locus of center is:

Options

A. `{(x,y):x^(2)=4y}uu{(x,y):yle0}`
B. `{(x,y):x^(2)+(y-1)^(2)=4}uu{(x,y):yle0}`
C. `{(x,y):x^(2)=y}uu{(0,y):yle0}`
D. `{(x,y):x^(2)=4y}uu{(0,y):yle0}`

Answer

D