Mark the letter A,...

Câu hỏi: Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
In most________developed countries, up to 50% of________population enters higher education at some time in their lives.

A. $\varnothing$/$\varnothing$

B. $\varnothing$/the

C. the/ a

D. the/ $\varnothing$