In the given case Mark is most likely to experience a slow-to-warm-up temperament.
Slow-to-warm-up can be defined as a character trait or a temperament of a child which is characterized by the child's uneasy and cautious behavior with the new situation or unfamiliar people.
The children having this behavior feel safe when they are surrounded by a few known or loved people and are not really happy with unknown or unfamiliar ones. They adapt to changes slowly and sometimes not at all.
The trait is shown by Mark therefore can be characterized as slow-to-warm-up.
Learn more about slow-to-warm-up here:
https://brainly.com/question/25741615