Which term refers to the gap between what a learner can accomplish alone and what he or she can achieve with guidance from more skilled partners

A)  the help zone
B)  the optimal period 
C)  the zone of accomplishment
D)  the zone of proximal development

The term that refers to the gap between what a learner can accomplish alone and what he or she can achieve with guidance from more skilled partners is the zone of proximal development, also known as ZPD. This concept was introduced by Lev Vygotsky, who believed that learning occurs when individuals engage in activities that are within their ZPD, where they can receive guidance and support from more experienced individuals.