Solving sqrt(i)=z, one or two solutions?

[parisse]

z=sqrt(i) is a polynomial equation of degree 1 in z, therefore it has a unique solution. z^2=i is a polynomial equation of degree 2 in z, therefore it has 2 solutions (in C). This is what is called d'Alembert theorem (in France) or fundemental theorem of algebra in English speaking countries (I think).
I wonder how can sasa pretend that the Prime answer is unexpected.