Final answer:
W.T. Miller supported the Populist ideal of bimetallism. Therefore, the correct option is A. bimetallism
Step-by-step explanation:
The Populist ideal that W.T. Miller supported, based on the lyrics of the song 'Free Silver and Bryan in 1900,' was bimetallism. Bimetallism is the monetary system in which both gold and silver are used as a standard for currency. Miller's lyrics mention giving silver a chance and having silver and gold share the burden in a ratio of sixteen to one, indicating his support for bimetallism.