Answer: Option(a) is correct
Step-by-step explanation:
Social mobility is defined as the shifting of social status of an individual in society , group or population from high to low or vice-versa.This mobility can be seen in families, household, employee etc.
It occurs due social changes that occur in life of a person as well as skill, talent and potential factors influence the change.Upward shift in social class is changing the position from low to high and downward shift refers to high to low social change.
Other options are incorrect because random factors, genetic flow and poverty culture change does not induce social mobility in society and population.thus, the correct option is option(a).