Which national football team won the AFC Asian Cup 2019 tournament?

Introduction / Context:
The AFC Asian Cup is the premier football championship for national teams in Asia. The 2019 edition of the tournament was widely followed, especially because it showcased the growth of football in West Asia and the emergence of new regional powers. This question checks awareness of international sports events and the performance of Asian national teams.

Given Data / Assumptions:
- The tournament in question is the AFC Asian Cup held in 2019.
- We are asked to identify the national team that won this tournament.
- The options list Japan, Argentina, Qatar and China.
- Football here refers to association football, also known as soccer.

Concept / Approach:
To answer, students must recall the outcome of the 2019 AFC Asian Cup final. Argentina is a South American team and does not participate in the Asian Cup, which helps eliminate at least one option. The focus should be on remembering that a West Asian team had a historic run in 2019, defeating several strong opponents and lifting the trophy for the first time. That team was Qatar, which used the tournament to signal its rise in Asian football ahead of hosting the FIFA World Cup 2022.

Step-by-Step Solution:
Step 1: Note that Argentina belongs to the South American confederation, so it cannot be the winner of an Asian confederation tournament. Step 2: Recall that in the 2019 AFC Asian Cup final, Qatar faced Japan. Step 3: Remember that Qatar played outstanding attacking football and defeated Japan in the final match. Step 4: Based on this recall, choose Qatar as the correct answer.

Verification / Alternative check:
One way to verify this memory is to connect it with the narrative of Qatar building a strong national team in the years before the FIFA World Cup that it hosted. The victory at the AFC Asian Cup 2019 was widely reported as a major milestone in this preparation. Japan already had multiple Asian Cup titles and was the runner up in this edition, while China did not reach the final. This supports the conclusion that Qatar is the correct choice.

Why Other Options Are Wrong:
- Japan: Reached the final but lost to Qatar, so it was the runner up, not the champion.
- Argentina: Not a member of the Asian Football Confederation and does not compete in the AFC Asian Cup.
- China: Participated in the tournament but did not win the title in 2019.

Common Pitfalls:
A common mistake is to remember that Japan is historically a strong Asian team and to assume it won again. Another error is not recognising that Argentina cannot be the winner because it belongs to a different continental confederation. Students should carefully connect the year 2019 with Qatar's breakthrough performance and the narrative of building momentum before the World Cup.

Final Answer:
The team that won the AFC Asian Cup 2019 was Qatar.