Based on the Work of Thomas Cech and Sidney Altman,why

Based on the work of Thomas Cech and Sidney Altman,why is RNA thought to have been the first type of genetic material?

A) RNA can be both a substrate and an enzyme.
B) RNA is made of nucleotides.
C) RNA is single stranded and more simple than DNA.
D) RNA can be converted into DNA.
E) RNA contains uracil which was abundant in the early atmospherE.