How does trees help us ?

Question

$\begin{array}{1 1} (a)\; \text{they reduce the temperature by absorbing sun rays} \\ (b)\; \text{they absorb carbon dioxide and releases oxygen} \\ (c)\; \text{they do not absorb pollutant gases } \\ (d)\; \text{They develop forest fires and destroy the surroundings} \end{array}$