Read the passage then answer the questions

iceland’s temperatures are actually mild. in the summer, the average high is about sixty degrees. winter temperatures are not as cold as one might expect. nighttime lows are usually around twenty-eight degrees. iceland experiences an extreme seasonal change in the length of day and night. during midwinter, the sun stays below the horizon all day long. in midsummer, the sun shines all night. pack a sleep mask if you plan to visit iceland in june or july. it might be the only way for you to get some shuteye!

what is the most likely reason the author suggests packing a sleep mask?

the number of activities in iceland is limited.
the capital city of reykjavik can be quite noisy.
the flight from new york city to iceland is long.
the sun shines all night in iceland during summer.