Choose the answer A, B, C or D

Exercise : Choose the answer A, B, C or D. 
1. Hi, this is my friend. She's from _ Philippines. 
A. the 
B. a 
C. x 
D. an 
2. Where's _ lake Victoria ? I think it's in _ east Africa. 
A. the / the 
B. x / x 
C. the / an 
D. x / an 
3. On average, _ moon is 384,400 km from _ Earth. 
A. the / the 
B. x / the 
C. a / an 
D. a / the 
4. Tourists from every corner of the world adore silk made by _ local residents in the area. 
A. the 
B. x 
C. an 
D. a 
5. My friend said she went to _ Ha Long Bay last week and it was _ unforgettable experience for her. 
A. the / the 
B. x / the 
C. x / an 
D. the / an 
6. What is the longest river in the world ? - Not sure _ Amazon ? 
A. x 
B. an 
C. a 
D. the 
7. I wish I would go on an adventure trip to _ Antarcitica someday. 
A. the 
B. a 
C. an 
D. x 
8. They were snowmobiling when they bumped into _ falling tree. 
A. a 
B. x 
C. an 
D. the 
9. _ Himalayas has many of the world's highest peaks, including _ Mountain Everest. 
A. The / a 
B. The / the 
C. A / a 
D. The / x 
10. It was my most memorable holiday in London. I had a chance to behold _ Thames. 
A. a 
B. the 
C. x