(b) and (c) only
(a), (b) and (c)
(a) and (b) only
(b) only
The correct option is (a), (b) and (c). The barrier potential depends on the type of semiconductor (for Si, Vb = 0.7 V and for Ge, Vb = 0.3 V), the amount of doping, and also on the temperature.