This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

[Q]: The printed circuit board industry defines heavy copper as layers exceeding three ounces of copper, or approximately 0.0042 inches (4.2 mils, 105 m) thick. PCB designers and fabricators often use heavy copper when design and manufacturing circuit boards in order to increase current-carrying capacity as well as resistance to thermal strains. Heavy copper plated vias transfer heat to external heat sinks. IPC 2152 is a standard for determining current-carrying capacity of printed circuit board traces.
[A]: What's the minimum amount of copper a layer in a PCB can have to be considered "heavy copper"?

[Q]: The last opus number that Chopin himself used was 65, allocated to the Cello Sonata in G minor. He expressed a deathbed wish that all his unpublished manuscripts be destroyed. At the request of the composer's mother and sisters, however, his musical executor Julian Fontana selected 23 unpublished piano pieces and grouped them into eight further opus numbers (Opp. 6673), published in 1855. In 1857, 17 Polish songs that Chopin wrote at various stages of his life were collected and published as Op. 74, though their order within the opus did not reflect the order of composition.
[A]: What was the last number Chopin gave to an opus?

[Q]: Later, during the Koine Greek period, the aspirated and voiceless stops /t d/ of Attic Greek lenited to voiceless and voiced fricatives, yielding / / in Medieval and Modern Greek.
[A]:
Attic Greek lenited to what?