#### Answer

C

#### Work Step by Step

$-3x\geq9\longrightarrow$ Divide both sides by -3 and switch the inequality symbol.
$-3x\div-3\leq9\div-3\longrightarrow$ divide
$x\leq-3$
This is shown by a graph with a closed circle at -3, where all the numbers to the left of -3 are highlighted.