As you travel up into the mountains, you notice discomfort in your ears. this is due to

a. the low pressure in your ears.
b. the low pressure at the bottom.
c. the low pressure in the mountain.
d. the high pressure in the mountains.

The correct answer is the low pressure in the mountains

Explanation:  

The air pressure is lower in the mountains. As we travel up into the mountains, the air inside our ears takes some time to adjust the pressure change.

This unequal pressure causes discomfort in ears while ascending and descending on the mountain. The condition of discomfort in ear is caused by the pressure difference between the outside and inside the eardrum.

Therefore, as we travel up to into the mountains, we notice discomfort in our ears. This is due to the low pressure in the mountain.