Which sentence contains correct parallel structure?
a) He wanted three things out of the class: to learn a new skill,to make new friends, and to develop a different mindset.
b) He wanted three things out of the class: learning a new skill, making new friends, and to develop a different mindset.
C) He wanted three things out of the class: learning a new skill, to make new friends, and to develop a different mindset.
d) He wanted three things out of the class: to learn a new skill, making new friends, and developing a different mindset.