Hi Hugo99
The question asks you how far can you walk, if you cannot walk any distance tick either (e) or (f) and explain why you cannot walk. The electric wheelchair is an aid, if you cannot use a manual wheelchair, explain why you cannot use a manual wheelchair and have to use an electric one, i.e cannot grip, no power to propel yourself.
The why part of not being able to do something is the important part. You need to paint a picture in words about your limitations.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
