Which of the following statements about aggregate planning is TRUE?

Which of the following statements about aggregate planning is TRUE?
 
  A) An advantage of the counterseasonal product and service mixing option is that it matches seasonal fluctuations without hiring/training costs.
  B) In aggregate planning, back orders are a means of manipulating supply while part-time workers are a way of manipulating product or service demand.
  C) A pure chase strategy allows lower inventories when compared to a pure level scheduling.
  D) A disadvantage of subcontracting is that it may require skills or equipment outside the firm's areas of expertise.
  E) The option of varying workforce size by hiring or layoffs is used where the size of the labor pool is small.