The equation of parabola is [tex] x=ay^2 [/tex]. If a is positive and [tex] y^2 [/tex] is always greater than zero or equal to zero, then x is also greater or equal to zero. This means that parabola is determined for non-negative x and for all real y.
Tha canonical equation of parabola is [tex] y^2=2px [/tex], where p>0. The branches of this parabola go up in positive y-direction. When you change x to y and y to x, then the branches of parabola go in positive x-direction, that is right.
Answer: correct choice is A.
