A fixed mass of an ideal gas is compressed at constant temperature. The pressure is recorded continuously as the volume decreases. The pressure ( y-axis) and volume (x-axis) are plotted on a linearly scaled graph.

Which statement describes the plotted line?

A. a curved line of increasing positive gradient starting at the origin of the graph

B. a curved line with negative gradient of decreasing magnitude

C. a straight line parallel to the pressure axis

D. a straight line parallel to the volume axis

E. a straight line of positive gradient starting at the origin of the graph