Here are the correct options for each question:

Question 1 [813742]: She wants to be ___ doctor when she grows up.
- C. a

Question 2 [813743]: Chris has an evening job as ___ office cleaner.
- B. an

Question 3 [813744]: ___ sun rises in the east and sets in ___ west.
- A. The - the

Question 4 [813745]: I had ___ little problem with my car, but it's been fixed now.
- B. a

Question 5 [813746]: Most of ___ international students have met their advisors, but a few of them have appointments next week.
- D. the

Question 6 [813747]: He started his working life as ___ engineer but later became ___ teacher.
- A. a - a