In this question, we are given two lines, AB and CD.
Now, the two new line segments (A'B' and C'D') are generated by translating the initial lines to left side.
For better understanding, let's have a look at the figure.
Generally, both the lines will overlap but I put it this way for better understanding.
Now, if we look at both the lines, then they will never overlap as they are parallel. Also, they are only translated to the left side, as given in the figure. Therefore, the distance would be the same as the distance between line AB and line CD. Therefore, the last option is correct.