Final Answer:
The expression that is True if and only if variable (c) is not equal to a string consisting of a single character 'x' is (c ≠ 'x').
Step-by-step explanation:
In programming, the expression (c ≠ 'x') checks whether the value associated with the variable (c) is not equal to the string 'x'. The inequality operator ((≠)) evaluates to True when the contents of (c) are different from the specified string. If (c) holds any value other than the string 'x', the expression is True, indicating that (c) is not equal to a string consisting of a single character 'x'.
This expression is particularly useful when you want to conditionally execute code based on the content of the variable (c). If the goal is to perform certain actions only when (c) is not equal to a specific string, this expression provides a clear and concise way to implement that logic. It helps enhance the flexibility and readability of the code, ensuring that the intended conditions are met.
In summary, the expression (c ≠ 'x') serves as a straightforward and effective way to verify that the value associated with the variable (c) is not equal to a string consisting of a single character 'x'. It is a common construct in programming languages to manage conditional statements and control the flow of the program based on the value of variables.