There is no right answer for you because it will depend on several things, such as the lenght of the application, your expertise in c#, the kind of desktop app as another user pointed out. That being said i will give you some tips.
First of all, MVC is a web oriented pattern, which aim is to improve cohesion between classes and have a clearly responsibility for each of its components. The view, does interact with the controller through requests, and the controller interacts with the model which interacts with the repository in order to generate a response for the client basically. So provided that you want a desktop app, this is a no go.
MVP pattern is the same pretty much the same (not really know it but i know its a derivate from the MVC pattern), but the presenter is the one that interacts with the model through interfaces, perhaps this is what you want since it can work with a win forms.
Those are my thoughts on the patterns you just mention, but i ll add something i work with.
I dont know the name of the pattern but i usually work with a layer structure similar to mvc but its not a pattern per say i think (i would gladly know if it its and please point it out in the comments). I work with basically 4 layers: Presentation, Data, Logic, Model. The responsibilities are, The presentation is the one that interacts with the user, whenever the user sends an input and it needs to interact with the repository you are using, you do it through the Logic layer, which has your business logic, then there is the Data logic, which is your repository basically, it doesnt know anything of how the data is rendered, it just knows that it needs to do CRUD operations on your repository.
In spite of what I said, you are saying you need a simple app, patters are a great work to build scalable apps, but it can take some work to set them up, and if the work you need to set them up overseeds the needs you have for your app then you are maybe poking the wrong tree here. And you basically can have all in 3 or 4 classes, dont try to make your program fit a pattern, they are to make our work easier not harder.