The diagram illustrates the change in an economy’s production possibility curve (PPC) from year $1$ to year $2$. What could account for the shift from year $1$ to year $2$?
- AResources have moved from the production of services to the production of goods.
- BThe number of workers unemployed in manufacturing has fallen.
- CThe producers of services have introduced better technology.
- DThe workers in the production of goods have become less efficient.