At the earth's north pole,for how long is the sun above the horizon?
A) about 24 hours
B) about 12 hours
C) it is always on the horizon
D) about six months
E) about one month

Dear player55,

The correct answer is: D) about six months

"At the North Pole, the sun rises around 21 March, sets around 21
September."
(National Snow & Ice Data Center: Polar Day and Night)

"As you can see, here at the North Pole the Sun spends half a year
above the horizon. The North Pole experiences six months of continuous
daylight and then six months of continuous darkness. Note the dates
the Sun appears and disappears, approximately 21st March and 21st
September. These are the dates of the equinoxes."
(University of Durham: Patterns of motion in the sky)

Sources:

National Snow & Ice Data Center: Polar Day and Night
http://nsidc.org/arcticmet/quickfacts/polar_day_night.html

University of Durham: Patterns of motion in the sky
http://www.dur.ac.uk/john.lucey/users/e1_cybersky.html

Search terms used:
"north pole" "above the horizon" "six months"
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"polar day"
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Hope this answers your question!
Regards,
Scriptor

I agree d is the only correct answer.  Neil