To the max means to the highest level or degree, and in this context the boy was trying to reach the highest shelf by stretching his arm to the farthest possible extent.
Context: "The boy was trying to reach the highest shelf, stretching his arm to the farthest possible extent, but couldn't achieve it."
Hypothesis: The boy was trying to reach the highest shelf, stretching his arm to the maximum, but couldn't achieve it.
Based on the context, is the hypothesis true, false, or unknown?