Correct option (B) 16
There are two sets of five parallel lines at equal distances. Clearly, lines like l1 , l3 , m1 , m3 form a square whose length of the diagonal is 2.
So, the number of required squares = 3 x 3
[Since, choices are (I1 , I3), (I2 , I4) (I3 , I5) for one set, etc.]