Fixing the compass at points P and T and drawing arcs which intersect below the line is likely to be his next step in constructing the perpendicular line.
In elementary geometry, the property of being perpendicular(perpendicularity) is the relationship between two lines which meet at a right angle (90 degrees). The property extends to other related geometric objects. A line is said to be perpendicular to another line if the two lines intersect at a right angle.
The correct answer between all the choices given is the third choice or letter C. I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.