Which of the following steps has not yet been accomplished by ...

[penguins]

Which of the following steps has not yet been accomplished by scientists studying the origin of life?
A) synthesis of small RNA polymers by ribozymes
B) abiotic synthesis of polypeptides
C) formation of molecular aggregates with selectively permeable membranes
D) formation of protocells that use DNA to direct the polymerization of amino acids
E) abiotic synthesis of organic molecules

[Millan]

I know it's D, we did this last week

[penguins]

Thank you, thank you!!