Ian accidentally spills a beaker of an unknown solution. It splashes onto the strip he used to test Solution 1, and the strip turns from red to blue. Based on this observation, which conclusion could Ian make about the solution that he spilled? a: The solution spilled on the strip must be neutral.

b: The solution spilled on the strip must have a basic pH.

c: The solution spilled on the strip must have a pH lower than 5.

d: The solution spilled on the strip must have the same pH as solution 1.