In quadrilateral JKLM, the exterior angle at vertex J measures 70∘, and the exterior angle at vertex L also measures 70∘. The interior angles at vertices K and M are each 70∘. Which of the following best describes JKLM?
a) It is a kite but not a parallelogram.
b) It is a cyclic quadrilateral.
c) It is a parallelogram.
d) It is an isosceles trapezium with JK∥LM.