@[deleted] - I assume you mean 20 league goals, if so he wasn't too far off it last season and he's going at a good pace this season, I think it was 10 in 12 starts.
Welbeck could develop to reach that target but it's all 'in theory' at the moment, in the mean time Giroud is already getting close to those figures so it's difficult to justify favouring for the former based on goal scoring. Danny needs to wait for his chance and grab it when he gets it. He was far too timid when he had the chance earlier this season.