Name the String

Another question type for a game/quiz-style app that I'm making. Given a note and a fret, you have to name the string (there is a choice of four answers below). Whereas I've used 12 lines on the right to represent the fretboard, I've tried to represent a note by using a musical staff.

I've turned on the guides to show how I've positioned the boxes on the page. The ratio's used are 2:3 in relation to the iPhone's resolution.