Answer:
The mechanism is most likely to be SN2.
Step-by-step explanation:
SN1 reaction is a two step reaction in which the first step is carbocation formation which is planar.The nucleophile can attack from either sides of it resulting in recemic mixture(both retention and inversion product is formed).
But SN2 reaction is a single-step process that is the leaving group leaves and the nucleophile attacks at the same instant.Hence the nucleophile attacks from the opposite side of the leaving group resulting in inversion product.
Hence mechanism is SN2.