Identify the target compound

Methyl phenyl ether is anisole, with structure: $\mathrm{Ph-O-CH_3}$

Best method for preparing ethers

A common method is Williamson ether synthesis: $\mathrm{R-O^-Na^+ + R'-X \rightarrow R-O-R' + NaX}$

This works best when the alkyl halide $\mathrm{R'-X}$ is primary, so that it undergoes $\mathrm{S_N2}$ substitution easily.

Check each option

Option A: Benzene, MeBr

Benzene does not contain an oxygen atom, so it cannot directly give anisole with methyl bromide. Also, this is not a valid ether synthesis condition.

Option A is incorrect.

Option B: $\mathrm{PhO^-Na^+}$, MeBr

Sodium phenoxide reacts with methyl bromide via Williamson ether synthesis: $\mathrm{PhO^-Na^+ + CH_3Br \rightarrow PhOCH_3 + NaBr}$ This gives methyl phenyl ether (anisole).

Option B is correct.

Option C: Ph-Br, $\mathrm{MeO^-Na^+}$

This would require nucleophilic substitution on an aryl halide ($\mathrm{Ph-Br}$). Aryl halides do not undergo normal $\mathrm{S_N2}$ reactions. Hence anisole is not formed under these conditions.

Option C is incorrect.

Option D: $\mathrm{PhO^-Na^+}$, MeOH

Methanol is not a good alkylating agent. It does not provide the methyl group to form anisole in Williamson synthesis.

Option D is incorrect.

Final answer

The suitable reaction condition is: $\boxed{\mathrm{PhO^-Na^+,\, MeBr}}$

So, the correct option is B.