The nurse did not know the information
Answer: 3. Exploration of Kepler-22b is unlikely to happen any time in the near future.

Context clues are clues in the text that surround a word. You can use them to understand the meaning of the word.
Another example besides the one provided is “She thought the computer was profitless, but it turned out to be very <em>valuable</em>.”
Using context clues such as the word “<em>valuable</em>,” you can get a good idea of what the word “profitless” means.