Noctilucent clouds are found in which sphere of the atmosphere?

Correct option is C

Noctilucent clouds (NLCs) are high-altitude clouds that form in the mesosphere, at altitudes of 75-85 km above Earth’s surface. They are the highest clouds in Earth’s atmosphere and are visible only during twilight.

Form in the mesosphere at very low temperatures (~ -120°C).
 Made up of tiny ice crystals that reflect sunlight after sunset.
Mostly seen in polar and high-latitude regions (50°-70° N/S).

Thus, the correct answer is:
 Mesosphere

Information Booster:

Why Are Noctilucent Clouds Special?

• Form above normal cloud levels.
• Appear silvery-blue due to sunlight scattering.
• Associated with climate change and increased water vapor in the mesosphere.

Additional Knowledge:

Lowest atmospheric layer, where humans live.
Contains 75-80% of atmospheric mass and almost all weather phenomena (clouds, storms, rain).
Temperature decreases with altitude (normal lapse rate: 6.5°C per km).

Stratosphere (12 - 50 km) – The Ozone Layer