Suppose $x$ Is a Random Variable Best Described by a Uniform Probability

Suppose $x$ is a random variable best described by a uniform probability distribution with $c = 3$ and $d = 9$ . Find the value of a that makes the following probability statement true: $\mathrm { P } ( \mathrm { x } \leq \mathrm { a } ) = 1$ .

A) $a \leq 3$
B) $a \geq 3$
C) $a \leq 9$
D) $a \geq 9$