A) Plane because it is a flat surface that extends in two dimensions but exists in a three-dimensional space, and also it isn't a point, a line, or an angle because a line is infinitely thin, a point is infinitesimally small, and an angle is a measurement, not a surface.
Use a all called math w.a.y (remove the periods) trust me it helps with at least 75% of math problems
The fourth root? There is no simplifying to be done.
The only way to continue work on this is converting to decimal. To four places the answer is 3.3437.
If you meant to ask for the cube root, the answer is 5.