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Question 75·Hard·Transitions

Astronomers hoped the new observatory would detect the universe’s earliest galaxies by collecting faint infrared light, a task possible only if the telescope’s instruments remained extremely cold. ______ the construction of the James Webb Space Telescope required the inclusion of a five-layer sunshield the size of a tennis court, and the mission team spent months rehearsing its complex deployment sequence.

Which choice completes the text with the most logical transition?