Specialization and trade based on comparative advantage allow nations to attain the following results, except

A) higher combined output.
B) higher consumption and standard of living.
C) rising total employment.
D) consuming combinations of products that are outside their PPCs.

While specialization and trade can lead to higher combined output and higher consumption and standard of living, it may not necessarily lead to rising total employment. In some cases, it may result in job losses in certain industries that are not competitive on the global market. However, the gains from increased productivity and efficiency in other industries can outweigh the losses in terms of employment. It is also important to note that specialization and trade cannot allow a nation to consume combinations of products that are outside their PPCs, as this is limited by the availability of resources and technology.