Water boils at 96 degree Celsius at mt Everest. Why ?

The correct answer is C : because of low atmospheric pressure. 

Atmospheric pressure is the pressure exerted by the atmospheric air in unit area on earth surface . Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa; 1,013.25 mbar), which is equivalent to 760 mm Hg, 29.9212 inches Hg, or 14.696 psi.

The standard, or near-average, atmospheric pressure at sea level on the Earth is 1013.25 millibars, or about 14.7 pounds per square inch. The gauge pressure in my automobile tires is a little more than twice that value.That pressure is called atmospheric pressure, or air pressure. It is the force exerted on a surface by the air above it as gravity pulls it to Earth. Atmospheric pressure is commonly measured with a barometer. ... Meteorologists describe the atmospheric pressure by how high the mercury rises.

Air pressure is caused by the weight of the air molecules above. ... This pressure causes air molecules at the Earth's surface to be more tightly packed together than those that are high in the atmosphere.When bulb is pressed, air present in tube and bulb escapes in the form of bubbles. However, there is atmospheric pressure on surface of liquid. When we release the bulb, the water moves inside the tube.

The reason we can't feel it is that the air within our bodies (in our lungs and stomachs, for example) is exerting the same pressure outwards, so there's no pressure difference and no need for us to exert any effort.When air is sucked out of a drinking straw, the air pressure inside if decreases and the atmospheric pressure outside forces the liquid to go inside the straw. ... Skis have a large area to reduce the pressure on the snow.As a fluid, air flows around you and tries to crush you in. Fortunately, there is typically just as much pressure inside your body pressing outward as there is air pressure outside your body pushing inward. They typically cancel out, meaning that there is no overall force on you and you don't get crushed.

Changes in barometric pressure that accompany storms and shifts in weather patterns do affect our bodies, and many people are more sensitive to those effects than others.