Step 1: Concept For a wave function ($\psi$) to be physically meaningful, it must satisfy specific boundary conditions known as "well-behaved" criteria.
Step 2: Meaning These criteria ensure that the probability density derived from the wave function is logically consistent.
Step 3: Analysis A valid wave function must be continuous, single-valued, and finite so that the electron cannot exist in two states at once or have infinite probability in a region. Option (D) suggests an integral $\le 1$; however, for a normalized wave function, the total probability of finding the particle in all space must be exactly equal to 1 ($\int \psi^2 d\tau = 1$).
Step 4: Conclusion The mathematical expression in option (D) as written (with mismatched limits and the inequality) does not represent a standard requirement for an acceptable solution.
Final Answer: (D)