Answer:
Scaffolding
Step-by-step explanation:
In psychology, the term scaffolding consists of the activities provided by an educator, parent or more competent peer, to support the student as he or she is led through the zone of proximal development (The zone that englobes what the student can do without help and the things he can do with the help of others).
In other words, scaffolding is a process that enables a child to solve a task that would be beyond his unassisted efforts, to do this, the adult needs to control the elements of the task that are beyond the kid's capability allowing him to complete the elements that are within his actual competence.
In this example, Rose noticed that his little brother was having difficulties putting a jigsaw together, so he began assisting him by praising his successes and offering occasional clues as to which piece to use so he could be successful.
In other words, his sister helped him complete a task that would be beyond his unassisted efforts by providing help in the "difficult parts".
Thus this is an example of scaffolding.