In __________ a person defends against anxiety by adopting behaviours opposite to her/his true feelings.

Reaction formation

The answer is Reaction formation.

In reaction formation, a person defends against anxiety by adopting behaviors that are opposite to their true feelings. For example, a person who is secretly angry at their boss may become excessively agreeable and helpful towards them. A person with strong sexual urges, who channels her/his energy into religious fervour, presents a classical example of reaction formation.

The other options are not accurate:

• Projection is a defense mechanism in which a person attributes their unacceptable thoughts or feelings to others.
• Rationalization is a defense mechanism in which a person makes up excuses or explanations for their unacceptable thoughts or feelings.
• Regression is a defense mechanism in which a person reverts to earlier, more childlike behaviors.