Final answer:
Firms in monopolistically competitive industries are likely to exit when they face sustained economic losses, especially in the long run where continuing operations would lead to further losses.
Step-by-step explanation:
Firms that are likely to leave an industry when facing economic losses are typically those in a monopolistically competitive industry. These firms, when confronted with sustained losses, undergo a process called exit. In the short run, a business might continue operating if it can cover its variable costs, despite making losses. However, in the long run, if the losses persist, the firm will cease production to stop incurring further losses. As firms exit the industry, the supply decreases, which may drive up prices and eliminate the economic losses for the remaining firms, bringing the industry back to a normal profit condition. The decision to exit is not taken lightly, as it often involves significant cost and impact on stakeholders.