How does the SLII model suggest leaders should match their leadership style to the development level of followers?

Leaders should always use a high directive$-$low supportive style $($S$1).$

Leaders should use a high directive$-$high supportive style $($S$2)$ regardless of development level.

Leaders should adopt a style based on a one$-$to$-$one relationship with the development level of followers.

D Leaders should never adapt their style but maintain a consistent approach.