I just need to know if I should be writing this as a command line application or GUI application. I'm doing this in C# so I have the option of either a Console App or A Windows Forms App.
They are asking for the source code and I don't know whether the grader is a person or a computer program because in part I, it graded each project way too quickly to be a person. I don't know how this one is going to be graded so I need to know if it/they are expecting a command line application or if they need it in gui.
That's a question for the Coursera team. There should be a form to request information and/or feedback from the instructor, though how well monitored it is is a different matter.
The basic text specified the interface as a console program (see Section 7.3.2).
I would imagine that the Coursera course would follow this approach IF they want to execute your code. But if they are allowing you to use any programming language, it is going to be hard for them to do that. Did they give you a set of programming language options to pick from?