Passage: Group D of the 2019 AFC Asian Cup took place from 7 to 16 January 2019. The group consisted of Iran, Iraq, Vietnam, and Yemen. The top two teams, Iran and Iraq, along with the third-placed team, Vietnam (as one of the four best third-placed teams), advanced to the round of 16.The group contained two former champions, Iran (3 titles) and Iraq (1 title). Yemen made its debut in the tournament.

Question: Who made an appearance in to tournament?
Yemen