Buy-out, buy-in, key resource acquisition, or takeover: which of the following examples is which?

1. Dean is buying Hess Construction, a sole proprietorship.
2. Sheri has purchased all the stock belonging to Nomi the current owner.
3. Bernell has acquired 75% ownership of Alcatraz Mini-Storage
4. Rudy is a raider and has purchased a controlling interest in Alltech Research and Development without the permission of the management.