In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
The 2020 Tokyo Paralympic Games began (1) ______ Tuesday night with the opening ceremony at Japan's National Stadium. The twelve-day sporting celebration (2) ______ a total of 539 events in 22 para (3) . The opening ceremony took place in (4) empty stadium. The Games should have (5) ______ place last year but were postponed because of the coronavirus pandemic.

Select the most appropriate option to fill in blank No. 4.

1. A
   an
2. B
   one
3. C
   the
4. D
   a