The correct answer is:

B one solution

A system of equations will have one solution if the graphs of the equations intersect at exactly one point on the coordinate plane. This point represents the unique solution to the system. If you can see only one intersection point in the graph, then there is one solution. If the lines are parallel, there would be no solutions (A), and if they are the same line, there would be infinitely many solutions (C). If the graph is unclear, then it might be undetermined (D).