Before 1928, scientists believed that all organic compounds only came from living organisms minerals dead things rocks

Before 1928, scientists believed that all organic compounds only came from living organisms. The word organic itself came from the word organism/s. This gave way to the old theory of "Vitalism" where scientists have long believed that synthesis of living organisms can be a way to harvest organic compounds. It was later proven that such is  not true because of the presence of urine, an inorganic compound found within organisms.

Answer:   d.  carbon dioxide.