Can anyone solve this one? The answer is B

Consider a rectangle of width 2 units and height 1 unit as shown below. We define the bottom left corner as (0, 0) then (2, 0), (2, 1) and (0, 1) going counter-clockwise from there. We then roll the rectangle along the base to form a cylinder of height 1, also shown below:

The points (1/4, 1/4) and (3/2, 3/4) are defined on the rectangle and a line is drawn between them on the cylinder. Find the length of this line