Answer:
1 ≤ x ≤ 6 Option A
Explanation:
When graph is constant it means, value of graph ( y-values) not to be change different values of x in given interval.
In other words, graph must be parallel to the x axis is known as the constant graph.
A function is a measure of the rate of change of function values with respect to change in input values.
In given graph horizontal line is lie on the interval from x ≥ 1 to x ≤ 6.
So, option A is correct.