Concept: The correct word must describe people who flatter or praise political leaders, often to gain personal advantage.
Explanation:A sycophant is someone who acts with excessive flattery toward an important person.
The phrase "who always praise their governments" clearly points to flatterers or praise-singers.
Therefore, "sycophants" fits the meaning of the sentence perfectly.
The other options do not fit: "parasites" depend on others, "allies" work with a shared purpose, and "favourites" are simply preferred persons.
So the completed sentence is: Some political leaders love sycophants who always praise their governments.
Answer: A. sycophants