下列化学反应中，属于分解反应的是（　　）

A．	$\mathit{Ca}（\mathit{OH}{）}_2+C{O}_2═\mathit{CaC}{O}_3\downarrow +H_{2}O$
B．	$2\mathit{KMn}{O}_4\begin{array}{c}\underset{¯}{\underset{¯}{\begin{array}{ccc}& △& \end{array}}}\\ \end{array}{K}_2\mathit{Mn}{O}_4+\mathit{Mn}{O}_2+O_2\uparrow$
C．	$\mathit{CaO}+H_{2}O═\mathit{Ca}（\mathit{OH}{）}_2$
D．	$F{e}_2{O}_3+3\mathit{CO}\begin{array}{c}\underset{¯}{\underset{¯}{\begin{array}{ccc}& \mathit{高温}& \end{array}}}\\ \end{array}2\mathit{Fe}+3C{O}_2$