Final answer:
Sam and Alex's relationship is entering the partnership phase, where they are expected to share trust, respect, and reciprocal obligations, representing a modern, cooperative manager/employee dynamic.
Step-by-step explanation:
When Sam offers Alex an opportunity to increase his responsibility within the group, their relationship is indicative of a transition into the partnership phase of the leader-member exchange theory. This phase is characterized by high levels of trust, respect, and mutual obligation. The partnership stage is typically where both parties actively contribute to the relationship, sharing influence and responsibility, which aligns with the changing trends in manager/employee dynamics towards a more egalitarian and cooperative model.