Answer:
Option A decreases with increase in altitude
Explanation:
This can be explained as the value of gravitational acceleration, 'g' is not same everywhere.
It has its maximum value at poles of the Earth and minimum on its equator.
Thus a person will weigh more at poles than equator.
This variation is in accordance to:

Thus the gravitational acceleration changes as inverse square of the Radius of the Earth.
Thus as we move away from the Earth's center, gravitational acceleration, g decreases.
A diameter is a straight line that begins at one end of the circle and ends at the opposite end. The condition for a line to be a diameter is that it must pass through the centre of the circle. If a line that touches two points on the circle, does not pass from the centre of the circle, it cannot be called a diameter.
The length of the diameter is the measurement of the line that connects the two points of the circle.
It goes in this order. Medium, density, viscosity
A mercury barometer is a device that is used to measure atmospheric pressure at a location. :)