Why Is It Unlikely That DNA Was NOT the First

Why is it unlikely that DNA was NOT the first self-replicating molecule of life?

A) nitrogen is essential for constructing DNA and there was no nitrogen on early Earth
B) DNA is hyper-sensitive to oxygen and would have disassembled quickly in its presence
C) DNA requires proteins like DNA polymerase for assembly so it doesn't truly "self-replicate"
D) it must have RNA to self-replicate and RNA evolved much later in life's history
E) more than one of these is correct