What is IUPAC name of the following compound?

Identifying the parent compound: The compound contains a benzene ring with hydroxyl, methyl, and aldehyde functional groups. The aldehyde group ($-\mathrm{CHO}$) has highest priority, establishing benzaldehyde as the parent compound.

Numbering orientation: The aldehyde carbon is assigned position 1. Both clockwise and counterclockwise numbering yield locant sets (1, 3, 5). Alphabetical priority requires that hydroxyl (lower alphabetical order than methyl) receives the lower locant number.

Naming: Substituents are listed alphabetically as 3-hydroxy-5-methylbenzaldehyde.

Among the options, only choice C corresponds to this systematic name. Phenol-based names (A and B) incorrectly prioritize the hydroxyl group, while D reverses the substituent positions.

The correct answer is $\boxed{\text{C}}$