According to Miller and Other Researchers,the Most Difficult Condition to Have

According to Miller and other researchers,the most difficult condition to have been met in an "RNA world" was to

A) produce specialized molecules, such as enzymes, lipids, and carbohydrates that supported life functions.
B) produce chemical reactions that would produce large molecules.
C) have converted clay particles into organic molecules.
D) synthesize molecules that would coalesce into the correct shape and structure of cells.
E) have established molecules that reproduce themselves.