68. Which of the following is true about the combination of mops and brooms represented by point E in Figure 1.3 and using PP1?
A. Point E is efficient now.
B. Point E is attainable if this economy uses more of its available resources.
C. Point E is unattainable if this economy becomes more efficient.
D. Point E is attainable only if more resources become available or technological advances are made.