DVDs Can Be Produced at a Constant Marginal Cost of $10

DVDs can be produced at a constant marginal cost of $10 per disk, and Roaring Lion Studios is releasing the DVDs for its last two major films. The DVD for Rambeau 17 is priced at $20 per disk, and the DVD for Schreck 10 is priced at $30 per disk. What are the Lerner indices for these two movies?

A) Both equal one.
B) 2 and 3, respectively
C) 0.5 and 0.67, respectively
D) 1 and 2, respectively