Etotal=KE+PE
For Etotal<Um,KE<0
∴ A→3
For Etotal=Um,KE=0
∴ B→1
For Etotal>Um, the particle has unbounded motion and there is no constraint on r.
∴ C→5,D→2
For 0>Etotal≥Um, at rmax and rmin velocity is tangential.
∴ radial component of velocity is zero.
∴ B→4.