In the following figure, triangle represents men, circle represents post-graduates and square represents sub-inspectors of police.

Which number represents female post - graduates, sub-inspectors of police ?

Given:
The triangle represents men.
The circle represents postgraduate persons.
The square represents police sub-inspectors.
From the above:
The region common to circle and square but outside the triangle represents female postgraduate police sub-inspectors.
From the diagram, this number is 12.
Therefore, the correct option is (d) 12.