Your friend, a coffee barista, joins a labor union that is organizing and campaigning for higher wages. She explains to you that while a higher hourly wage would be nice, what really motivates her to join is a strong sense of injustice about how little she earns, compared to how hard she works. Which type of incentive appears to be motivating your friend to participate in this interest group? Tangible incentive Solidary incentive Material incentive Purposive incentive