Answer: Its the third pair which can be proven by the HL theorem
Step-by-step explanation:
HL theorem states that if hypotenuse and one leg of two right triangles are congruent then the triangles are said to be congruent.
In first picture there is two right triangle with equal hypotenuse but not any leg. So HL theorem cannot be applied.
In second picture there is no right triangle. So HL theorem cannot be applied
In third triangle there is two right triangle with equal hypotenuse and legs therefore by HL theorem they are congruent.
In fourth picture they are not right angle. So HL theorem cannot be applied