James defines a circle as "the set of all the points equidistant from a given point." His statement is not precise enough because he should specify that
O a circle includes its diameter
O the set of points is in a plane
O a circle includes its radius
O the set of points are collinear

A circle has a center, radius, diameter and points in a plane. Depending on the context, the definition of a circle must contain at least one of the following terms:

Based on James' definition of a circle, he needed to specify that the points are in a plane (option c).

As presented in his definition "the set of all the points" can be interpreted in several ways. Some of which are:

Of this numerous possible interpretation, James should have specified that the set of points is in a plane

Learn more about circles at:

c is the final : )