What did Billy and Carly do during their extended holiday?

I - They sang their favorite songs during breakfast.
II - They went to the beach.
III - They hiked in the mountains.
IV - They wrote the first chapter of their biography.
V - They read some books in the evening to relax.
VI - They visited their friends who live in the countryside.
VII - They cycled with their new bikes.
VIII - They cooked their dinner with a portable stove.
IX - They played the guitar to practice the chords.
X - They listened to Rolling Stones on the way to the mountains.
a. I, II, III, IV, V, VI, VII, VIII, IX, and X.
b. I, II, III, IV, V, VI, VII, VIII, and IX.
c. I, II, III, IV, V, VI, VII, and VIII.