Reaction of (R)-2-Chloro-4-Methylhexane with Excess NaI in Acetone Gives Racemic

Reaction of (R) -2-chloro-4-methylhexane with excess NaI in acetone gives racemic 2-iodo-4-methylhexane.What is the explanation that best describes this transformation?

A) an S_N2 reaction has occurred with inversion of configuration
B) racemization followed by an S_N2 attack
C) an S_NI reaction has taken over resulting in inversion of configuration
D) an S_N1 reaction has occurred due to carbocation formation
E) an S_N1 reaction followed by an S_N2 "backside" attack