Which of the following types of costs are prime costs?
  a.Direct materials and overhead.
  b.Direct materials and direct labor.
  c.Direct materials, direct labor, and overhead.
  d.Direct labor and overhead.
  Answer:B
  Choice "B" is correct. Prime costs are normally defined as direct materials and direct labor.
  Choice "a" is incorrect. Direct materials and overhead do not represent prime costs. Prime costs are direct material and direct labor.
  Choice "d" is incorrect. Direct labor and overhead are normally referred to as conversion costs, not prime costs.
  Choice "c" is incorrect. Direct materials, direct labor, and overhead comprise total costs, not simply prime costs.