Concept:The idiom "be under a cloud" means being viewed with distrust or suspicion.
Explanation:When someone is under a cloud, others believe they may have done something wrong.
It does not mean simply feeling sad or gloomy, though that feeling may follow.
It has no connection to working secretly as an undercover agent.
It also does not mean hiding one's own mistakes or misdeeds.
Instead, it describes the state of being suspected or disgraced in the eyes of others.
Answer:Option A — To be the object of suspicion.