The number next to the base in a mathematical expression is called an exponent. The exponent represents the number of times the base is multiplied by itself. In the given options, the correct answer is option b. Exponent. To determine the answer, you need to understand the concept of exponents and their role in mathematical expressions. An exponent is typically written as a superscript to the right of the base number. For example, in the expression 2^3, the base is 2, and the exponent is 3.
