Final answer:
Contact ulcers are caused by actions that put stress or irritation on the vocal cords, except for psychogenic problems, which are not a direct cause.
Step-by-step explanation:
Contact ulcers, also known as vocal fold ulcers, are small sores that develop on the cartilages of the back of the larynx. The causes of contact ulcers include chronic throat clearing, hard-glottal attack (forceful starting of vocal sounds), and prolonged intubation during surgery. However, psychogenic problems, which refer to psychological issues that may manifest as physical symptoms, are not a known direct cause of contact ulcers. Therefore, psychogenic problems would be the correct answer to the question: Contact ulcers may be caused by all of the following except for psychogenic problems.