The diagram below shows part of the rock cycle. three rectangles are shown arranged at the perimeter of a circle. the top rectangle has rock a written inside it. the bottom right rectangle has rock b written inside it and the bottom left rectangle has rock c written inside it. the arcs of the circle from the bottom right rectangle points towards the top rectangle and towards the bottom left rectangle. the arc from the bottom left rectangle points towards the top rectangle. magma is written at the center of the circle. an arrow points from the top rectangle towards magma. an arrow points from the bottom right rectangle towards magma and another arrow parallel to it points from magma towards the bottom right rectangle. which type of rock does c represent?