Break-even revenue for the multiple-product firm can
  a.  be calculated by dividing total fixed cost by the overall contribution margin ratio.
  b.  be calculated by dividing segment fixed cost by the overall contribution margin ratio.
  c.  be calculated by dividing total fixed cost by the package contribution margin.
  d.  be calculated by multiplying total fixed cost by the contribution margin ratio.
  e.  not be calculated; break-even revenue can only be computed for a single-product firm.