Question: I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "In 1979, the committees began the redistribution of land in the Jefara plain, continuing through 1981. In May 1980, measures to redistribute and equalize wealth were implemented; anyone with over 1000 dinar in his bank account saw that extra money expropriated. The following year, the GPC announced that the government would take control of all import, export and distribution functions, with state supermarkets replacing privately owned businesses; this led to a decline in the availability of consumer goods and the development of a thriving black market."?
Answer:
When did the GPC take control of all import, export, and distribution functions?