Why does water boil at temperature below 100°C at higher altitudes?

A) The atmospheric pressure decreases and hence boiling point is lowered

B) The gravitational attraction is less

C) Because of heavy winds in mountains

D) None of the above is correct

This MCQ is part of the UP PSC Previous Year Questions (PYQs) series, focusing on UPPSC Prelims 1994 (GS Paper I)