1. Interpret the substituted benzene ring

   The compound has three substituents on benzene:

   • one methyl group,
   • one chloro group,
   • one nitro group.

2. Apply IUPAC numbering rule

   For a trisubstituted benzene, we must number the ring so that the substituents get the lowest set of locants.

   From the given arrangement, if we assign:

   • methyl as position 1,
   • chloro as position 2,
   • nitro as position 4,

   then the locant set is: $1,2,4$

   This is lower than alternatives such as: $1,3,4,\, 1,4,5,\, 1,2,5$

   Hence the correct numbering is:

   • 1-methyl
   • 2-chloro
   • 4-nitro

3. Write substituents in alphabetical order

   Prefixes are written alphabetically:

   • chloro
   • methyl
   • nitro

   Therefore the name becomes: $\boxed{2\text{-chloro-}1\text{-methyl-}4\text{-nitrobenzene}}$

4. Check options

   • A: 2-methyl-5-nitro-1-chlorobenzene → numbering not lowest.
   • B: 2-chloro-1-methyl-4-nitrobenzene → correct.
   • C: 3-chloro-4-methyl-1-nitrobenzene → locants not lowest.
   • D: 5-chloro-4-methyl-1-nitrobenzene → locants not lowest.

So, the correct option is B.