Accurate answer is (d) None of the mentioned
For the easiest explanation: △V value is the same regardless of whether it is computed from the change in low dc supply or change in +Vcc or -Vee . For example, suppose that -Vee remains constant at -10v then the +Vcc has to vary from 8 to 12v as a result of change in low dc voltage. This means that the change in △V in supply voltage +Vcc is 2v in either direction from 10v.