Answer:
[tex]\text{A. }1\leq x \leq6[/tex]
Step-by-step explanation:
A constant intervals occurs when the function is neither increasing or decreasing. In the graph, we see this occurs from [tex]x=1[/tex] to [tex]x=6[/tex]. Therefore, the interval in which the graph is constant is [tex]\boxed{\text{A. }1\leq x \leq6}[/tex]
