Assertion : At high altitude a person, from plain areas, may experience altitude sickness.
Reason : At high altitude atmospheric pressure is generally high leading to symptons like nausea, fatigue, etc.

Answer

C

Explanation

At high altitude, a person may experienced altitude sickness. Its symptoms include nausea, fatigue and heart palpitations. It is due to the low atmospheric pressure of high altitudes that the body does not get enough oxygen.