Please help to modify the \draw[ ->] in tikzpicture to have the overset effect \overset{..}{\to}?

I want to include the \overset{}{\to} and \overset{}{\rightarrow} over the \to or the arrow in the following tikzpicture.

\begin{figure}[!h]\begin{center}\begin{tikzpicture}\matrix[matrix of math nodes,inner sep=1pt,row sep=1em,column sep=1em] (M){& A &  B & C \\& E &  F & G \\};\draw[ ->] (M-1-2.east) -- (M-1-3.west);\draw[ ->] (M-1-3.east) -- (M-1-4.west);\end{tikzpicture}\end{center}\end{figure}

So the the output of tikzpicture will have something similar to this overset or stackrel type in tikzpicture?

$A \overset{ab}{\to}  B \overset{bc}{\to}  C$

QUESTION

How should we modify the \draw[ ->] in tikzpicture then?