Which best describes what is happening in section B

The general form of the quetion of a circle is ax^2+by^2+cx+dy+e=0 where a=b=0 if the circle has a radius of three units and the center lies on the y axis which set of values of a, b, c, d, and e might correspond to the circle

Select the sequences that are geometric.

Which number produces a rationale number when multiplied by 1/5