These are the options for the question :Which one of the following compounds is more reactive towards SN1 reaction?

a. CH2=CHCH2Br
b. C6H5CH2Br
c. C6H5CH (C6H5)Br
d. C6H5CH(CH3) Br

The correct answer is -c C6H5CH (C6H5)Br
C6H5CH (C6H5)+ carbocation formed is more stable