A. They consist of team members who are shared across multiple initiatives at a time, since then they can take advantage of time otherwise spent waiting to do productive work.

B. They consist of people who have mostly deeply specialized skills.

C. They consist of team members who work only on one product and team at a time, so that they can focus.

D. They consist of team members who have broad enough skills to do many kinds of work, but who are not deeply specialized in any one area.