To determine the coordinates of point C after dilation by scale factor k=1/2, you have to multiply each coordinate of the original point by the scale factor, following the rule:
First, determine the coordinates of C. The point is over the x-axis, so the y-coordinate is zero, the x-coordinate can be read from the graph, it is x=2
C(2,0)
Calculate the dilation as follows:
The coordinates of point C after the dilation are C'(1,0)