A．not yet using postage stamps B．collecting valuable stamps C．buying stamps from Neuritis D．printing their own stamps
单项选择题$ 16,800 is the collector's value of （）
A．the One Penny Orange-Red B．a correctly printed'1847 stamp C．the Two Penny Blue D．both A and C
单项选择题The best title for this selection is （）
A．The "Post Paid" Error B．The Two Penny Blue C．A Rare Stamp D．How Mauritius Became Famous
