Aspirin is known as:

Aspirin is produced by treating salicylic acid (o-hydroxybenzoic acid) with acetic anhydride. In this reaction the phenolic -OH group of salicylic acid is acetylated, giving the ester $$\mathrm{o{-}AcO{-}C_6H_4{-}COOH}$$.

The IUPAC‐accepted common name for this product is acetyl salicylic acid. None of the other options match this structure:

• Phenyl salicylate (Option B) is an ester of salicylic acid with phenol, not acetic acid.
• Acetyl salicylate (Option C) lacks the word “acid” and does not convey that one specific hydrogen remains unacetylated.
• Methyl salicylic acid (Option D) would be an O- or C-methyl derivative, which is different from the acetylated compound.

Therefore the correct description of aspirin is:

Option A which is: Acetyl salicylic acid