Choice C is correct. A system of two linear equations in two variables, and , has no solution if the graphs of the lines represented by the equations in the xy-plane are distinct and parallel. The graphs of two lines in the xy-plane represented by equations in slope-intercept form, , where and are constants, are parallel if their slopes, , are the same and are distinct if their y-coordinates of the y-intercepts, , are different. In the equations and , the values of are each , and the values of are and , respectively. Since the slopes of these lines are the same, and the y-coordinates of the y-intercepts are different, it follows that the system of linear equations in choice C has no solution.
Choice A is incorrect. The lines represented by the equations in this system are a vertical line and a horizontal line. Therefore, this system has a solution, , rather than no solution.
Choice B is incorrect. The two lines represented by these equations have different slopes and the same y-coordinate of the y-intercept. Therefore, this system has a solution, , rather than no solution.
Choice D is incorrect. The two lines represented by these equations are a horizontal line and a line with a slope of that have the same y-coordinate of the y-intercept. Therefore, this system has a solution, , rather than no solution.