Got to second interview, now what?

[Reluctant]

I finished my MSc with a D(i know). And got past the first round interview for a IT position, and they want me back for a second round where they want me to present a project or assignment Im proud of. The most obvious thing would be my thesis, but I got a D in it so how can I even be serious about it?

Can I use a recent app Im developing and present it without looking like a goof?

 

Thanks.