A student comments, "Time is a continuous variable. We should really be looking at the Upper X double overbarX and Upper R overbarR values." Do you agree or disagree? A. One should agree because the time can be measured along a continuous scale and Upper X double overbarX and Upper R overbarR values are usually used for continuous variables. B. One should disagree because here the on-time delivery is important rather than the average time taken to deliver the order. C. One should disagree because as long as time is a continuous variable, a p chart should be used to track the sample proportions. D. One should disagree because the Upper X double overbarX and Upper R overbarR values should be used for both continuous and attribute variables