What Was St. Patrick's Battalion

What was St. Patrick's Battalion?

A) It was a group of American Protestants who sought to convert Catholic Mexican soldiers and prisoners of war by force in the name of peace.
B) It was a group of northern senators that had steadfast support for the Union and refused to entertain the idea of allowing slavery to enter the West following the Mexican-American War.
C) It was an American army unit that saw little combat and came to be highly involved in American journalism, including through undercover missions during the Texan Revolution.
D) It was a Mexican army unit made up entirely of Irish and German immigrants that deserted from the American army for reasons such as higher wages and mistreatment for their religion.
E) It was a group of pioneers who courageously formed search parties to recover wayward travelers, served as guides, and charted maps of undiscovered territory at great personal risk.