What does it mean to 'stupefy' a person?

To 'stupefy' a person means to make them less alert or to render them in a state of shock or bewilderment. The term implies a reduction in mental clarity or consciousness, often resulting from some overwhelming experience, substance, or event. When someone is stupefied, they may be unable to think or respond effectively, indicating that their usual state of awareness has been impaired. This aligns precisely with the choice indicating a decrease in alertness.