What is the correct IUPAC name of the following compound?

The principal functional group in the given compound is the carboxylic acid group ($-CO_2H$).

According to IUPAC priority rules,

$$\text{Carboxylic acid} > \text{Hydroxyl} > \text{Halogens/Nitro}.$$

Hence, the parent compound is benzoic acid.

The carbon atom attached to the carboxylic acid group is assigned position $$1$$.

Now, the ring is numbered in the direction that gives the lowest possible set of locants for the remaining substituents.

Clockwise numbering gives:

• $$2$$ : Hydroxy ($-OH$)
• $$3$$ : Bromo ($-Br$)
• $$5$$ : Nitro ($-NO_2$)

This produces the locant set

$${2,,3,,5}.$$

Counter-clockwise numbering gives:

• $$3$$ : Nitro ($-NO_2$)
• $$5$$ : Bromo ($-Br$)
• $$6$$ : Hydroxy ($-OH$)

This produces the locant set

$${3,,5,,6}.$$

Since

$${2,,3,,5} < {3,,5,,6},$$

the clockwise numbering is selected.

The substituents are therefore located at:

• $$3$$-Bromo
• $$2$$-Hydroxy
• $$5$$-Nitro

Finally, the substituent prefixes are arranged alphabetically:

• Bromo
• Hydroxy
• Nitro

Hence, the correct IUPAC name is

3-bromo-2-hydroxy-5-nitrobenzoic acid.

Therefore, the correct answer is:

(A) 3-bromo-2-hydroxy-5-nitrobenzoic acid