What year did standing for the usa national anthem begin?

There are historical data that tell us that the habit of standing during the national anthem happened during a ceremony at West Point in the year 1891. However, in 2009 there are data that at an NFL sports ceremony , it was established that the players had to remain standing as the American anthem sang. In 1918, as an extra data, it began to popularize playing the anthem in baseball games, to encourage people to attend the game even in times of World War I, and later also played in American football.

B,c and d are the answers

Iwould like a photo instead of all this and you can’t just go out asking for a paragraph thinking someone will be like oh yeah here it is