Which of the following is not a type of inequality?

• A. Less than
• B. Greater than or equal to
• C. Subtract
• D. Not equal to

Answer: (C)

The answer is correct because inequality refers specifically to mathematical expressions that compare two values or quantities, indicating a relationship between them. The terms “less than,” “greater than or equal to,” and “not equal to” are all standard forms of inequality that express a relationship where one value is either smaller, larger, or distinct from another.

In contrast, "subtract" refers to an arithmetic operation rather than a comparison of values. It describes the process of taking one number away from another, which does not convey inequality in the way the other terms do. Thus, "subtract" is not a type of inequality, reinforcing that the correct answer identifies a fundamental misunderstanding of the concept of inequality in mathematics.