documentclass{beamer}

% In Preamble
tikzset{
% Two node styles for game trees: solid and hollow
solid node/.style={circle,draw,inner sep=1.5,fill=black},
hollow node/.style={circle,draw,inner sep=1.5}
}
begin{document}
begin{frame}
begin{tikzpicture}[scale=0.9,font=footnotesize]
% Specify spacing for each level of the tree
    tikzstyle{level 1}=[level distance=15mm,sibling distance=35mm]
    tikzstyle{level 2}=[level distance=15mm,sibling distance=15mm]
% The Tree
node(0)[hollow node,label=above:{$Challenger$}]{}
    child{node(1)[solid node, label=above:{$Incumbent$}]{}
        child{node[label=below:{$(a,b)$}]{} edge from parent node[left]{$C$}}
        child{node[label=below:{$(c,d)$}]{} edge from parent node[right]{$D$}}
        edge from parent node[left,xshift=-3]{$A$}
}
    child{node(2)[label=below:{$(0,3)$]}{} edge from parent node[right, xshift=3]{$B$}
    };

end{tikzpicture}
end{frame}
end{document}