2 QUESTIONS HELP PLZ...:/

Which of the following is not part of the structure of a comet?

A. Coma
B. Head
C. Dust tail
D. Nucleus

How far can light travel in one year?

A. 300,000 km
B. 30 million km
C. 10 trillion km
D. 100 billion km

THANKS IF ANYONE CAN HELP =)