Jack and jim sign up with an online music store. jack chooses 15 downloads for $19.75, and jim chooses 40 downloads for $43.50. both amounts include a one-time registration fee, which is the same for each account, plus the fee for the number of downloads. what is the registration fee, and what is the cost of each download? a.) the registration fee is $5.50, and the cost per download is $0.95. b.) the registration fee is $3.50, and the cost per download is $1.00. c.) the registration fee is $2.50, and the cost per download is $0.85. d.) the registration fee is $4.75, and the cost per download is $1.00.