Final answer:
Statement a describes a change in quantity supplied. Statement b describes a change in quantity demanded. Statement c describes a change in supply. Statement d describes a change in demand.
Step-by-step explanation:
Statement a describes a change in quantity supplied. An increase in price leads to an increase in the quantity supplied by lamp producers.
Statement b describes a change in quantity demanded. An increase in price leads to a decrease in the quantity demanded of lamps.
Statement c describes a change in supply. An increase in profitability for making lamps leads to furniture makers reducing the production of tables and increasing the production of lamps.
Statement d describes a change in demand. An increase in people buying bigger houses leads to an increase in the demand for lamps.