You are going to have to do a search to get the exact photo on this......That has been answered many times over. Someone posted a photo with all the changes. I can say this much...... Version A - the carbon fiber looks completely different. Version B, the carbon fiber has a military pattern and they started throwing in prop locks because the props were coming off. Version C - I think it had the QR Props and Version D, the landing gear designed internally was changed to be a little smoother. I hope that helps.
Also, if you bought it brand new......on the box next to the serial number is a large A, B, C or D. Easy to see without having to open the box.