Read this and answer the question. If the question is unanswerable, say "unanswerable".

The process of selectio resembles eclectic textual criticism, but applied to a restricted set of hypothetical hyparchetypes. The steps of examinatio and emendatio resemble copy-text editing. In fact, the other techniques can be seen as special cases of stemmatics in which a rigorous family history of the text cannot be determined but only approximated. If it seems that one manuscript is by far the best text, then copy text editing is appropriate, and if it seems that a group of manuscripts are good, then eclecticism on that group would be proper.

What process is not used when there are a number of viable manuscripts available?
unanswerable