We hope you didn't hesitate to choose D. "Hesitate," "waver," "vacillate," and "falter" mean to show indecision or uncertainty. "Hesitate" implies a pause before deciding, acting, or choosing, as in "She hesitated before answering the question." "Waver" implies making a decision but then changing your mind or becoming unsure, as in "They wavered in their support of the candidate." "Vacillate" implies the inability to reach a firm decision, as in "He continued to vacillate between joining the drama club or the basketball team." "Falter" suggests failing to continue on a chosen course and often suggests nervousness or fear, as in "We never faltered in our determination to win."