Function choose 

pub fn choose(
    path: &Path,
    state: Option<&Path>,
    id: &str,
    n: usize,
    constraints: &[String],
    questions: &[String],
    via: Via,
    basis: &str,
) -> CommandResult

The person’s choice in session: approach n (1-based) with the constraints and open questions as they keep and add them. Composes and stores the brief; no model call.