Display empty values in Webform select list (radio) charts

I have been successful in accomplishing most functionality needed for a personal training website requiring feedback about trainers. The feedback is collected using a Webform to gather the feedback. Getting a Webform grid field to gather data was not possible due to a responsive website and the last few columns not being visible on older smartphones. This has resulted in a few 'select list' (radio) used to gather data but nevertheless are displayed very cleanly on all mobiles.

The problem I have run into is that after feedback is obtained, unless a option has been selected by a trainee, that field with no values is not displayed at all in a column chart. The attached image illustrates what I havent been able to ask very eloquently.

Is there any possible way I can display the empty values too (all select options) in a column chart? And as a bonus, how do I get rid of the key for this particular chart? Not sure if I should have posted it at 'Webform Chart' issues but I thought it is more relevant here.

Many thanks and will be grateful for any help