Answer: a. stranger anxiety
Step-by-step explanation:
Stranger anxiety is a developmental stage in infants typically of the age 8-18 months. In this condition, children develop anxiety during the time they are separated from their parents and exposed to people whom they are unfamiliar. Children feel unsafe and threatened. The symptoms of stranger anxiety may include many forms such as some infants will become quiet and will stare warily at the stranger, others will cry a lot, some children may hide themselves behind parents.
On the basis of the above description, Baby Polly is demonstrating stranger anxiety.