What was the main purpose of the antisaloon league In the early 1900s?

The correct answer is C to pass a constitutional amendment outlawing alcohol.

They did manage to pass it because they became one of the most powerful organizations when it came to prohibition lobbying. They managed to pass it and that's when the prohibition began in the first half of the 20th century. It didn't last very long and the constitution was changed to revert it back to normal.