The correct answer is C. National Labor Union
Step-by-step explanation:
William Sylvis was an American leader during the 19th century, mainly known for its role in labor unions. Indeed, Sylvis was the first member of a trade union movement Philadelphia, later he supported different unions during the civil war and finally, he decided to create a labor and trade union as he dreamt of a union that integrated multiple workers and sectors. In this way, by 1866 William Sylvis founded the National Labor Union, which as the first union of this kind and integrated multiple local unions. Therefore, the name of the union William Sylvis founded was the "National Labor Union".