Which of the following in not true

a$.$ PORT$-$Change interrupt occurs when the state of any of the pins $RB4,RB5,RB6,RB7$ changes

b$.$ GIE bit in INTCON registered must be enabled, otherwise no interrupts will occur

c$.$ It is not possible to enable multiple interrupts.

d$.$ Both RETFIE and RETURN pop the address of the next instruction to be executed from the stack