I think that this is the first question in the quiz - if it is, it might not be alphabetical, with opener referring to the first instance in which can or tin is used?
The quiz ends 31/12 in aid of St Marys Church Rushden Mission funds. The answers are in alphabetical order, The first must begin with A, also contain can or tin. Yes I had tin/can opener then realised it doesen't begin with A
The quiz says nothing about the alphabet. I think that as said earlier, it is because it has opener in the answer.
Tin opener is better. Can is American!