What defines an attitude?

An attitude is defined as a state of mind based on beliefs and values, making this the correct choice. This definition captures the essence of what attitudes are—they are not simply transient opinions or feelings but rather deeply ingrained perspectives that are often influenced by an individual's values and beliefs. These foundational aspects shape how a person interprets experiences, interacts with others, and reacts to various situations.

When we consider the other options, the statement about a temporary opinion pertains more to fleeting thoughts and doesn't encapsulate the long-lasting nature of attitudes. The notion of a fixed and unchanging viewpoint suggests rigidity, overlooking the fact that attitudes can evolve over time based on new experiences or information. A measurable emotional response implies a quantifiable emotional state, which does not address the cognitive and evaluative components that define attitudes.

Thus, the selection highlighting attitude as a state of mind rooted in beliefs and values provides a comprehensive understanding of its formation and influence on behavior.