A plot of land must be divided between four families. They want their individual plots to be similar in shape, not necessarily equal in area. The land has equally spaced poles, marked as dots in the below figure. Two ropes, R1 and R2, are already present and cannot be moved. What is the least number of additional straight ropes needed to create the desired plots? A single rope can pass through three poles that are aligned in a straight line.

To divide the total plot of land into $4$ sub-plots of similar shape using the minimum number of additional straight ropes:

1. Notice that the entire boundary of the plot is a pentagonal shape (a square with two chamfered/cut corners at top-right and bottom-left).

2. Existing ropes are:

   • R1: a horizontal segment covering $2$ unit grid intervals (spanning $3$ poles) at the lower-left section.

   • R2: a vertical segment covering $2$ unit grid intervals (spanning $3$ poles) at the upper-right section.

3. By adding 3 additional straight ropes of length $2$ units each:

   • One horizontal rope across $3$ poles parallel to R1,

   • One vertical rope across $3$ poles parallel to R2,

   • One connecting segment,

   the entire plot gets partitioned into $4$ non-overlapping regions, each geometrically similar to the others (each being a 5-sided polygon with identical corresponding angles and proportional side lengths).

Thus, the least number of additional ropes needed is 3.

Hence, the correct option is (D).