Read the passage given below and answer the following questions: The polarity of carbon-halogen bond of alkyl halides is responsible for their Nucleophilic substitution, elimination and their reaction with metal atoms to form organ metallic compounds. Nucleophilic substitution reactions are categorized into SN1 and SN2 on the basis of their kinetic properties. Chirality has a profound role in understanding the reaction mechanisms of SN1 and SN2 reactions. SN2 reactions of chiral alkyl halides are characterized by the inversion of configuration while SN1 reactions are characterized by racemisation. ASSERTION -REASON TYPE A statement of assertion is followed by a statement of reason. Mark the correct choice from the options given below: (a) Both assertion and reason are true and reason is the correct explanation of assertion. (b) Both assertion and reason are true but reason is not the correct explanation of assertion. (c) Assertion is true but reason is false. (d) Assertion is false but reason is true. (i) Assertion : SN2 reactions do not proceed with retention of configuration. Reason : SN2 reactions proceed in a single step. (ii) Assertion : Tertiary alkyl halides show high reactivity in SN1 reaction. Reason : Tertiary carbocation has more stability. (iii) Assertion : Nucleophilic substitution reaction in an optically active alkyl halide gives a mixture of enantiomers. Reason : Reaction occurs by SN1 mechanism. (iv) Assertion : Primary allylic halides show higher reactivity in SN1 reactions than other primary alkyl halides. Reason : Intermediate carbocation is stabilized by resonance.