Final answer:
Option (2) The lines describe the hyperbolic brightness and beauty of a woman's eyes, comparing them to a celestial body that could turn night into day.
Step-by-step explanation:
In the lines "...her eyes in heaven Would through the airy region stream so bright That birds would sing and think it were not night" (2.2.20-22), what is being described is the imagined brightness and beauty of a woman's eyes. This poetic expression compares her eyes to a celestial body so luminous that it could make birds believe it is daytime due to its brilliance.
The context here is not literally about the brightness of the moon, the beauty of the night sky, the singing of birds, or the darkness of the night, but about the hyperbolic glorification of a woman's gaze – in essence, romanticizing her eyes as resplendently shining like stars or perhaps brighter than them. This metaphor is meant to emphasize her beauty, suggesting that it is so powerful it could transform night into day.