Consider the system, it dx = (r- 1)x+ rxe " , which statement is true? the system exhibits a supercritical pitchfork bifurcation at r = 0. the system exhibits a saddle-node bifurcation at r = 0. the system exhibits a transcritical bifurcation at r = 1. the system exhibits a subcritical pitchfork bifurcation at r = 0