Correct choice is (d) RB || β × (Re + re‘)
To explain I would say: The input impedance of a simplified common collector (CC) amplifier can be expressed in terms circuit resistor values. The base impedance is RB || β × (Re + re‘) . Where β is the transistor amplifiers current gain, Reis the equivalent emitter resistance, RB is the equivalent base resistance and re‘ is the alternating current resistance of the emitter-base diode.