Which of the following is not considered a valid reason for denying a real estate license?

Age discrimination is not considered a valid reason for denying a real estate license because denying someone a license based solely on their age would violate anti-discrimination laws. In the context of licensing, these laws are designed to ensure that individuals are not treated unfairly based on factors such as their age.

In contrast, background check discrepancies, failure to meet educational requirements, and poor credit history are all legitimate factors that can affect a candidate's eligibility for a real estate license. For instance, failure to meet education requirements directly reflects on a candidate's preparedness for the responsibilities of a real estate agent. Similarly, background check discrepancies may indicate issues related to criminal activity or dishonesty, which are significant concerns in the real estate industry where trust and integrity are paramount. Poor credit history can also suggest financial irresponsibility that could impact a candidate’s ability to perform effectively in their role as a real estate professional.

Therefore, the option that pertains to age discrimination stands out as it aligns with the principles aimed at ensuring equality and preventing discriminatory practices in licensing.