Final answer:
The manager's response of 'I'm fine' to Maria's question about her well-being illustrates emotional masking or emotional concealment.
Step-by-step explanation:
In this scenario, Maria notices her hunched-over manager and asks if she is okay because she appears upset. However, the manager responds by saying, 'I'm fine.' The manager's response is an example of emotional masking or emotional concealment. This is when someone hides or suppresses their true emotions, often presenting a false front to others.