Let us consider the following expression tree.

Select one or more:

a$.$ The postfix notation is f e c$/*$ d h $++$

b$.$

The infix notation is: $\frac{f+e}{c}**(d+h)$

c$.$ The postfix notation is fe $\frac{?}{?}\frac{d}{h}+**+$

d$.$ The postfix notation is $f+e\frac{c}{*}*dh+$

e$.$ The postfix notation is $fe(\frac{c}{d})h+**+$

f$.$ The infix notation is: $f+\frac{e}{c^{**}}(d+h)$