Question：Alan Castle is a sole practitioner. He has recently been asked to provide one day's training for a local charity. He has provisionally agreed the date and accepted their daily rate of $1,500. On checking his diary, however, Alan discovers that he has planned to meet with a client, Ms Chan, on the provisional date. At the meeting Alan is due to collect $2,000 outstanding from the most recent audit of Ms Chan's company. If Alan does agree to accept the date of the training course, he will have to cancel the meeting with Ms Chan.
　　What type of cost does the $2,000 represent?
　　A. An opportunity cost.
　　B. A non-relevant cost.
　　C. An avoidable cost.
　　D. A relevant cost.
　　The correct answer is: A non-relevant cost.
　　解析：The $2,000 is a non-relevant cost. The $2,000 which is due to be collected at the meeting is not material in Alan's decision to cancel his meeting, as the $2,000 will still be collectable.
　　The $2,000 is not an opportunity cost because it is not the cost Alan will forgo for not being present at the preplanned meeting.
　　The $2,000 is not an avoidable cost. The $2,000 is income that is outstanding.
　　The $2,000 is not relevant to any decision taken to cancel the meeting.