What Ingredient Was Not in the Original Waldorf Salad?

And the answer is ...

c) walnuts

Although walnuts have become a staple of any classic Waldorf salad, they weren't in the original dish when it was invented in NYC in the 1890s. By the 1920s, however, they had been integrated into the salad, which had become so popular that Cole Porter wrote about it in his 1934 Broadway musical, Anything Goes!