Which of the following statements are false? (You may select more than one answer) a. The planning horizon for discretionary fixed costs is longer than the planning horizon for committed fixed costs. CONCEPT CHECK b. Discretionary fixed costs can be cut in the short term if necessary, while committed fixed costs cannot be cut for short periods. c. As companies increasingly rely on knowledge workers, the labour cost associated with employing these workers is often committed fixed as opposed to discretionary. d. A mixed cost contains both committed fixed and discretionary elements