I think it would be A.) but at the same time i think it's wrong
See the attached picture:
We need a line to answer this question...
C is the answer. (X) can’t be repeated
We are given the coordinate of the 3 vertices. From these coordinates we can find the length of the sides using the distance formula and the sum of all the sides will be equal to the perimeter of the triangle.
Side PQ =

Side QR =

Side RP =

So, the perimeter of the triangle will be 8 + 4.5 + 7.2 = 19.7
You probably misplaced the digits in option A. The correct answer is 19.7 units.