Mark the letter A,B,C or D on your answer sheet to show the underlined part that needs correction in each of the following questions

Mark the letter A,B,C or D on your answer sheet to show the underlined part that needs correction in each of the following questions.
1. It was 1993 that the Complex of Hue Monuments was recognized as a World Heritage Site by UNESCO.
A. 1993.
B. That.
C. Was.
D. By.
2. It was the museum shop that I bought the photos of Hoi An Ancient Town.
A. The museum shop.
B. Bought.
C. Of.
D. Ancient.
3. Becoming dependent is important for teenagers, especially when they leave school.
A. Becoming.
B. Dependent.
C. Teenagers.
D. Leave.