Answer:
Thomas and Chess would say his temperament is B. slow-to-warm-up.
Step-by-step explanation:
When a child has slow-to-warm-up temperament, it is understood that he/she is cautions and often nervous about new situations where he/she does not feel comfortable. He/she needs to be able to trust someone, for example.
In this case, we can see Egbert is quiet and it is not easy for him to adapt to change. By the name, it can be deduced that a gradual introduction to others will help him be less distressed and be able to accept new situations and people.