The distance between two points is given by:
where A(x1,y1) and B(x2,y2).
In this case we are going to use the points given in the problem and the origin, which have coordinates O(0,0). Then the distances are:
From the distances above we conclude that:
Less than 15 units:
A
D
Exactly 15 units:
C
Greater than 15 units:
B
E