How can a poorly tuned engine affect fuel consumption?

• It can decrease fuel consumption by up to 50%.
• It can increase fuel consumption by up to 30%.
• It can increase fuel consumption by up to 40%.
• It can increase fuel consumption by up to 50%.
  Explanation:

  "A poorly tuned engine can increase fuel consumption by as much as 50%. Regular maintenance, such as tuning the engine, ensures it runs efficiently, saving fuel and reducing emissions while improving overall vehicle performance."