Which statement best explains why $25^{1/2}$ is defined as $5$ and not $-5$?

Because the base, 25, is a positive number.

To ensure the expression has a single, unique value, which is a requirement for functions.

Because negative numbers are not allowed as outputs for fractional exponents.

Because the denominator, 2, is the smallest even number.

Fractional Exponents Practice — Grade 4 amc_math