Cost classification by activity type Classify the following costs as unit-related, batch-related, product-sustaining, or business-sustaining activity costs.

(a) Packing labor wages

(b) Materials-handling labor wages

(c) Part administrators'salaries

(d) Plant management salaries

(e) Production scheduling staff salaries

(f) Equipment maintenance

(g) Property taxes

(h) Production expediters' salaries

(i) Insurance for plant facility

(j) Plant security

(k) Workers' training

(l) Electricity usage

(LO 1, 3)