Interesting card. Blank back with no advertising and caption in German (or ???): So I wouldn't give it an ACC letter designation. I could not find it in the World Tobacco Index either, so it must not be tobacco related.
Here are the ones I have listed on Todd's website (I'm sure there are more):
Mail Carriers And Stamps (C19) Imperial Tobacco Company Of Canada US 1903
Mail Of All Nations (D73) Rochester Baking Company US 1930-1949
Stamps & Mail Carriers Of All Nations (D73) Crispy Top Bread US 1930-1949
Stamps & Mail Carriers Of All Nations (D73) Schmidt's Bakery US 1930-1949
Mail Carriers Of All Nations (E163) Ghirardelli Co. US 1920's
Mail Carriers And Stamps (E239) Apollo Chocolates US 1920's
Mail Carriers And Stamps (E239) Mansfield Company US 1920's
Delivery Of Mail (F353) Schorn & Brower US 1930-1949
Delivery Of Mail (F354) McCormick Spice Company US 1930-1949
Mail Carriers And Stamps (H630) (Multiple Companies) US 1900-1919
Mail Carriers And Stamps (K138) International Coffee Company US 1900-1919
Mail Carriers And Stamps (K138) Frank, Frederick US 1900-1919
Mail Carriers And Stamps (K138) Manning, E.N. Co. US 1900-1919
Mail Carriers And Stamps (K138) Voskamps US 1900-1919
Mail Carriers And Stamps (K138) Sherman Bros. & Co. US 1900-1919
Mail Carriers And Stamps (T132) Unknown Tobacco Company US 1900-1919
Here is the same card with English text: