Which of the following can revoke a handgun permit in Tennessee?

In Tennessee, being committed to a mental institution involuntarily can indeed result in the revocation of a handgun permit. This law is rooted in the state's efforts to ensure that individuals who may pose a risk to themselves or others are not permitted to carry firearms. The mental health background is a significant factor in determining an individual's right to possess a handgun, reflecting the understanding that mental health issues can impact one's judgment and safety.

The other choices listed do not lead to a revocation of a handgun permit. For instance, having a concealed carry permit and participating in a firearm training course are typically part of the process to obtain or maintain a permit, serving as measures of responsible gun ownership. Additionally, holding a valid driver’s license is unrelated to firearm possession laws and does not affect an individual's eligibility for a handgun permit. Thus, the only scenario among the options that directly aligns with the legal grounds for revocation is that of involuntary commitment to a mental institution.