Which of the following is a primary halide 

Neo-hexyl chloride is a primary halide as Cl atom is attached to a primary carbon. IUPAC name of Neo-hexyl chloride is 1-chloro-2,2-dimethylbutane which indicates that the parent carbon chain is butane and in the second carbon, two methyl groups are attached whereas the Cl atom attached in the 1st carbon.

${\mathrm{CH}}_3-\mathrm{C}{\left({\mathrm{CH}}_3\right)}_2-{\mathrm{CH}}_2-{\mathrm{CH}}_2-\mathrm{Cl}$