I think (b) for SN2 because for OH- to attack (b) would provide less steric hindrance.
So answer for SN1 wud be (a)
I think (b) for SN2 because for OH- to attack (b) would provide less steric hindrance.
So answer for SN1 wud be (a)
The two look like:
The green is a Benzene atom cloud. See what can be guessed from here with the appearance.