Tikzpicture position in itemize item

I’m trying to add a Venn diagram to my math homework. I figured out how to make the diagram but my problem is that the diagram is not under the itemize item it should be.

Here’s my simplified LaTeX.

documentclass{article}
usepackage{tikz}

begin{document}
section{Task 1}
begin{itemize}
item[a)]
    Here's the first solution.
item[b)]
    begin{tikzpicture}
        draw (0,0) ellipse (4cm and 2cm) node [left = 2cm] {Thing 1};
        draw (1cm, 0) ellipse (2cm and 1cm) node {Thing 2};
    end{tikzpicture}
end{itemize}
end{document}

And here’s the output of the LaTeX.

Why is the b) under the diagram? How can I position the diagram so that the b) is at the "start" of the diagram?

documentclass{article}
usepackage{tikz}

begin{document}
section{Task 1}

begin{itemize}
item[a)]
    Here's the first solution.
item[b)]
    begin{tikzpicture}[baseline=(current bounding box.north)] % <---
        draw (0,0) ellipse (4cm and 2cm) node [left = 2cm] {Thing 1};
        draw (1cm, 0) ellipse (2cm and 1cm) node {Thing 2};
    end{tikzpicture}
end{itemize}

end{document}