Although the police officer sympathised with poor (1)/ he refused to (2) /take an action against the rich man (3). /No error (4)

Answer

1

Explanation

the will be used before poor because – the (Def. Art.) is used with Adjectives to refer to a thing or a group of people described by the Adj. Look at the examples given below:
The poor always suffer.
`darr " " darr`
Def. Art. Adj. (refers to a group of people who are poor) He is collecting money for `underset("Def.Art")underset(darr)("the blind")` .
blind refers to a group of people who are blind.