Select the sentence that demonstrates correct grammar usage.

a. riding a bike, playing a guitar, and also television are my favorite things to do with my free time.

b. when her neighbor surprised her by mowing her lawn, trimming her hedges, and washing her car, emma was incredibly grateful.

c. john's plans included rugby, attending college, becoming a lawyer, marrying his high school girlfriend, and kids.

d. gemma's parents are never home because they are too busy the poor, going out to eat, and their jobs are stressful, and going to see movies.