The answer is A, subduction :)
The answer to your question is DRIED PLANT MATTER ❤️
It is false, temperatures in the tundra do not get extremely high
"1. moisture (water vapor) in the air near the surface
2. instability - relatively large decrease of air temperature with height
3. lift - some process (such as a front) that forces air to rise"
The air is dry during the summer and any moisture amount is increased in the afternoon as the temperature cools.