“Double monopoly markup”

a) “Monopolies in factor market leads to exploitation of labor unlike competitive factor market”. Discuss the statement mathematically and graphically.
b) Discuss (graphically) the problem of “double monopoly markup” faced by consumer. How this problem can be minimized?
c) Discuss the concept of “pareto efficient” and “pareto inefficient/improvement” graphically. We discussed that perfect competition leads to “pareto efficient” allocation of resources. What are the circumstances that led society to allocate resources at “pareto inefficient” point?