Which word in the passage is the synonym of “doubtful”?

Directions: Read the given passage carefully and answer the following question.

The manager of a firm published an advertisement for a night watchman. He called many people for the interview. All the applicants were present. He interviewed almost everybody. But, the manager was not satisfied. He found something dubious with each man. There was Raju, an applicant. He was sitting in a corner waiting for his turn of interview. Manager found nothing wrong in his appearance. He questioned about his health. He got the reply that he was suffering from sleeplessness. Manager was happy and appointed him. Be real in life.