The cost of watching videos on a website is represented by C(a) = 3.00a + 4.00, where a is the number of videos watched. The cost is increased by $15.00 if the downloading feature is enabled. Identify the new function H(a) for the cost of watching downloadable videos and the transformation that has been applied. A: H(a) = 3.00a + 19.00; shift 15 units up
B: H(a) = 18.00a + 4.00; shift 15 units up
C: H(a) = 18.00a + 4.00; shift 15 units down
D: H(a) = 3.00a + 19.00; shift 15 units down