The dictator of that country was a monster of wickedness, insatiable in his ________ for blood and plunder.

Correct — C, 'lust'. 'Insatiable' means impossible to satisfy, so it needs a noun of craving after it — an appetite that can never be filled. 'Lust' names exactly that kind of hunger, and a lust for blood and plunder matches the portrait of a monster of wickedness.

Why the others are wrong

• (a)
  idea — An idea is a thought, and thoughts are not described as impossible to satisfy.
• (b)
  vision — A vision is something imagined or foreseen; it carries no sense of a craving that could go unmet.
• (d)
  intention — An intention is a settled plan, either carried out or not, so it cannot go endlessly unfulfilled the way an appetite can.

'Insatiable' selects the noun it modifies — only a word for hunger, thirst or desire can follow it comfortably.

Key facts

• 'Insatiable' means incapable of being satisfied.
• 'Lust' means an overwhelming craving and is not confined to the sexual sense.
• The words 'monster of wickedness' set a strongly negative register for the whole sentence.

Common traps

• Choosing 'intention', which fits the grammar but not the adjective.
• Rejecting 'lust' because only its narrow sexual sense comes to mind.

No directly related past PYQ was found.

• practice — not a real PYQ

  She had an ________ appetite for detective novels.

  • (a)insatiable
  • (b)inevitable
  • (c)insufferable
  • (d)insensible
  Answer(a) insatiable — it means impossible to satisfy.
• practice — not a real PYQ

  His ________ for power destroyed every friendship he had.

  • (a)vision
  • (b)idea
  • (c)lust
  • (d)notion
  Answer(c) lust — 'lust' names an overpowering craving.