What Detailed Rationale(s)might Be Suggested for Woese's Choice of SSU

What detailed rationale(s) might be suggested for Woese's choice of SSU rRNA sequencing to determine phylogenetic relationships? (Select all that apply)

A) the complexity of interactions between ribosomal RNA and transcription proteins make these molecules unlikely to develop random mutations.
B) the complexity of interactions between ribosomal RNA ,ribosomal proteins,mRNAs and tRNAs and make these molecules unlikely to develop random mutations.
C) Due to the position of rRNA genes on the archaeal chromosome,mutation is unlikely to occur
D) The central role in cell survival played by this molecule makes it highly conserved and reliable as a comparative sequence across all life forms.
E) All are valid justifications for woese's choice