The correct option is C 1-bromo-3-methyl butane
Since there are four carbon in the parent chain, parent chain will be butane. Numbering will start from the side where substituents gets lowest possible numbers i.e. from bromine side (in this compound). So, Br will get number = 1 and methyl group will get number = 3. Out of bromine and methyl, bromine will be written first because of alphabetical order.
Therefore, I.U.P.A.C name of compound is 1-bromo-3-methyl butane