Pentagon pqrst and its reflection, pentagon p'q'r's't', are shown in the coordinate plane below: pentagon pqrst and pentagon p prime q prime r prime s prime t prime on the coordinate plane with ordered pairs at p negative 4, 6, at q negative 7, 4, at r negative 6, 1, at s negative 2, 1, at t negative 1, 4, at p prime negative 4, negative 6, at q prime negative 7, negative 4, at r prime negative 6, negative 1, at s prime negative 2, negative 1, at t prime negative 1, negative 4 what is the line of reflection between pentagons pqrst and p'q'r's't'?