Close to f/2.8
The closest my standard lens comes to selective sharpness is f/4.5, so that’s what I used here.
The “composition” of the still life is just as they happened to be lying on the table. It is almost a matter of principle to me that I take reality as given and do not interfere to make compositions “better” than what fate gives me. Exception: blades of grass or dead leaves and similar small things that I can easily take away.
Looking at the photo, I don’t like the horizontals of the courgettes in the middle: they break the dominant verticals in the composition, and therefore take attention away from the area of sharpness, more in the foreground. Though that is a little better in the original large-size photo: there you see that the courgettes are really out of focus and the sunflowers stand out very clearly (or rather: sharply) from the dark-green background. (That effect is one of the reasons why you should never judge photos in the small screen on the back of your camera: sharpness and bokeh are very different in the original size.)