DVDs Can Be Produced at a Constant Marginal Cost of $5

DVDs can be produced at a constant marginal cost of $5 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 price elasticities of demand for these two movies?

A) Both equal -1.2.
B) -0.75 and -5/6, respectively
C) -1.33 and -1.2, respectively
D) -1.33 and -2, respectively