Answer:
(A) social change and availability of talent.
Step-by-step explanation:
Any change in the status of any individual or group of people is called social mobility. It is the movement of any category of people in a social strata or hierarchy. It can be upward or downward depends on the movement from the current social position of an individual. While some people restrict social mobility because it threatens to break society modern opportunities have provided enough space for it. For example, a child who works hard in academics can escalate his social position.