Which of the following products can be obtained from the above reaction?

Match the reactants in Column-$(I)$ with the products formed in Column-$(II)$.

Column-$(I)$ (Reactants)	Column-$(II)$ (Major Products)
$(A)$ $C_6H_5CH_3 + X_2 \xrightarrow{Fe, \text{dark}}$	$(i)$ $C_6H_5CH(Br)CH_3$
$(B)$ $C_6H_5NH_2 \xrightarrow{NaNO_2, HX, 273-278 \ K}$	$(ii)$ $C_6H_5N_2^+X^-$
$(C)$ $C_6H_5N_2^+X^- \xrightarrow{Cu_2X_2}$	$(iii)$ $p-X-C_6H_4CH_3 + o-X-C_6H_4CH_3$
$(D)$ $C_6H_5CH_2CH_3 \xrightarrow{Br_2, \Delta \text{ or } UV \text{ light}}$	$(iv)$ $C_6H_5X$

Identify the product in the following reaction:

Match the List-$I$ with List-$II$:

List-$I$ Name reaction	List-$II$ Product obtainable
$A.$ Swarts reaction	$I.$ Ethyl benzene
$B.$ Sandmeyer's reaction	$II.$ Ethyl iodide
$C.$ Wurtz Fittig reaction	$III.$ Cyanobenzene
$D.$ Finkelstein reaction	$IV.$ Ethyl fluoride

Choose the correct answer from the options given below:

Match the reactants in Column-$I$ with the products in Column-$II$.

Column-$I$ (Reactants)	Column-$II$ (Products)
$(A) CH_3CH_2Br + Mg \xrightarrow{\text{dry ether}}$	$(i) \text{Cyclohexylmagnesium bromide}$
$(B) 2RX + 2Na \xrightarrow{\text{dry ether}}$	$(ii) CH_3CH_2MgBr$
$(C) CH_3CH_2Br \xrightarrow{\text{alc. KOH}}$	$(iii) R-R + 2NaX$
$(D) \text{Bromocyclohexane} + Mg \xrightarrow{\text{dry ether}}$	$(iv) CH_2=CH_2 + H_2O + KBr$

Given below are four compounds:
$(a)$ $n$-propyl chloride,
$(b)$ $iso$-propyl chloride,
$(c)$ $sec$-butyl chloride,
$(d)$ $neo$-pentyl chloride.
Percentage of carbon in the one which exhibits optical isomerism is: