Answer:
Option C is the right choice.
Step-by-step explanation:
The given coordinates define a rectangle, and our objective is to show that the diagonals JL and KM are congruent.
We know that rectangles possess four right angles.
To prove the congruence of the diagonals JL and KM, we will utilize the Pythagorean theorem.
In triangle KLM, KL has a length of b units while LM has a length of a units. By applying the Pythagorean theorem 
In triangle JML, JM is b units long, and LM remains a units long. We again can apply the Pythagorean theorem
Thus, we find that
and option C is the correct choice.