On a LP problem consider you have a constraint: X$1>=28000$ and through the sensitivity analysis you find that the value for this constraint can go up to $36000$ without impacting the optimal solution. Which one of the following statements is correct?

A$.$ X$1$ is a binding constraint with a surplus value of $36000.$

B$.$ X$1$ is a nonbinding constraint with a surplus value of $36000.$

C$.$ X$1$ is a nonbinding constraint with a surplus value of $8000.$

D$.$ X$1$ is a binding constraint with a surplus value of $8000.$