The figure below shows triangle pqr and some of its transformed images on a coordinate grid: a coordinate plane is shown with five triangles. triangle pqr has vertices 2 comma 1, 5 comma 1, and 2 comma 4. triangle a has vertices negative 2 comma 1, negative 5 comma 1, and negative 5 comma 4. triangle b has vertices negative 6 comma 1, negative 6 comma 4, and negative 9 comma 1. triangle c has vertices negative 2 comma negative 1, negative 2 comma negative 4, negative 5 comma negative 4. triangle d has vertices 2 comma negative 1, 5 comma negative 1, and 5 comma negative 4. which of the four triangles was formed by a translation of triangle pqr?