The answer is A. m = undefined, C'D' = 13.2 units. When you dilate both C and D with the scale factor 2.2 with the origin as the center of dilation, their coordinates respectively become the following:C' (22, 13.2) and D (22,26.4)
The difference between 26.4 and 13.2 is 13.2. The slope is undefined since it is s vertical line.
Hope i helped