Bolivia has about 50% of the world's reserves of lithium. It is also a major producer of zinc. Suppose that Bolivia produced only those two goods and that its linear production possibilities frontier had the following endpoints: 20,000 tons of lithium and zero zinc, or 10,000 tons of zinc and no lithium. A combination of 10,000 tons of lithium and 5000 tons of zinc would be:__________
a) attainable and efficient.
b) attainable, but not efficient.
c) efficient but not attainable.
d) unattainable.