Step 1: Analyze the constraints.
From the image of the shaded region, we can deduce the constraints based on the lines and regions formed by the given conditions. These include the boundaries of the axes, the line equations, and the limits on \( x \) and \( y \).
Step 2: Conclusion.
Thus, the linear constraints are \( 5x + 9y \leq 90, \quad x + y \geq 4, \quad y \leq 8, \quad x, y \geq 0 \), corresponding to option (D).