SN1 reaction mechanism and carbocation stability

2020 Phase-2 1 question

1. Which of the following will NOT undergo $S_N1$ reaction with $OH^-$? [add image: (1) benzyl chloride (2) $CH_2=CH-CH_2Cl$ allyl chloride (3) $(CH_3)_3CCl$ tert-butyl chloride (4) 2-phenylethyl chloride ($C_6H_5CH_2CH_2Cl$)]