答案：C

解析：

"Impulsive" means acting suddenly, abruptly, or without premeditation. To approve something is to consent to or confirm it. The sentence suggests that the department head was concerned about how her actions would be viewed. If she were concerned about the possibility of being considered too abrupt or thoughtless in her plans, or about thinking them through insufficiently before acting on them, she certainly might have wanted to have her plans "approved" by others before she implemented them, or carried them out. It makes sense to say that the department head had the advisory committee members confirm or sanction her plans so that she would not be considered impulsive.