Final answer:
Among the options listed, manipulating concrete objects is not a core component of mastery learning; instead, mastery learning involves logical topic sequencing, mastering units before proceeding, and providing additional remedial activities. Therefore, the correct option is B.
Step-by-step explanation:
The component that is not necessarily a component of mastery learning is: b. students have many opportunities to manipulate concrete objects. Mastery learning focuses on arranging topics in a logical sequence, ensuring students demonstrate mastery before proceeding, and providing remedial activities for mastery.
The manipulation of concrete objects is more specific to hands-on learning environments or subjects that require physical manipulation, such as sciences or the arts, rather than a core component of mastery learning which can be applied to various subjects including theoretical or abstract ones.