Answer:D. a phobia
Explanation:
A phobia is an anxiety dosorder that causes someone to have extreme fear of a particular object or subject or a situation. A person with a particular phobia will do whatever it takes , extreme measures to avoid exposure to that situation or object. These measures may seem unreasonable when one looks at the object that is feared. A person may even faint at the sight of the object that they extremely fear.
There are different types of phobias which an social phobia ,specific phobia and agoraphobia.
Specific phobia relate to extreme fears of animals ,blood and other specific situations. Social phobia is fear of being judged.
David has a specific fear of clowns such that he presumably think they are that dangerous and one can't take their kids to see them.