A newspaper article on Britain' s unions argued that their strength was declining. The article' s evidence was the decreasing number and size of strikes, as if the reason for the unions' existence was to organize strikes. Surely, in a modern industrial society, the calling of a strike is evidence that the negotiating position of the union was too weak. Strong unions do not need to call strikes. They can concentrate their efforts on working with others in the labor market to achieve common goals, such as profitable and humane working conditions. The argument criticizing the newspaper article is directed toward establishing which one of the following as its main conclusion? ["The reason for unions' existence is to work for goals such as profitable and humane working conditions by organizing strikes.", 'Although unions represent the interests of their members, that does not preclude them from having interests in common with other participants in the labor market.', 'There is no reason to believe, on the basis of what the newspaper article said, that union strength in Britain is declining.', 'The negotiating position of a union is weak if the only means it has of achieving its end is a strike or the threat of a strike.']