Imagine the sun rising from the mountain at sunrise. Then find the highest point in the lowest boundary. According to the monotonicity of the function. The maximum point may appear at the intersection of hyperbola and two straight lines. Find two intersections respectively. The intersection on the left is 1, and the intersection on the right is 6 minus the root number 5. Because the right intersection is larger, the answer is 6 MINUS the root number 5. The following four options have no correct answers.