Susie is playing with blocks and is trying to build a tower; she tries but cannot build a tower. Susie's mother helps her build a four-block tower. Later, Susie builds a four-block tower without her mother's help. According to Vygotsky, the inability to build the tower on her own is known as:

a) Zone of proximal development
b) Scaffolding
c) Private speech
d) Cognitive dissonance

Susie's initial inability to build a tower but later success with her mother's help exemplifies the zone of proximal development, where learning occurs with support.

Explanation:

The scenario with Susie not being able to build a tower on her own but then being able to do so with her mother's help represents the concept of the zone of proximal development (ZPD). Lev Vygotsky’s theory articulates that the ZPD is the difference between what a learner can do without help and what they can achieve with guidance and encouragement from a skilled partner. In Susie's case, her initial inability to build the tower falls within her ZPD because she is capable of building it with the scaffolding provided by her mother.

Option 'a' is the correct answer—Zone of proximal development—since it describes Susie's situation of being able to perform a task with assistance that she initially could not do alone. Scaffolding is the support given during the learning process, tailored to the needs of the student with the intention of helping the student achieve his or her learning goals. Susie's experience reflects the importance of social interactions and the supportive role of more competent individuals in cognitive development.