For Gabriel synthesis halides should be primary.
a.1-bromopentane -primary
b.1-bromo-3-methylbutane -pimary
c.2-bromo-3-methylpentane -secondary - cannot be used
d.1-bromo-2,3-dimethylbutane -primary
e.2-bromo-2,3-dimethylbutane- tertiary -cannot be used
I think it should be like this