The
correct answer is (c).
Although it is
probably true that the largest number of cases will be identified
by this approach, this may or may not serve the interests
of the study. On the plus side, the distribution of cases
available for analysis at the end of the study will probably
include a broad range of severity---from mild to very severe.
This may facilitate informative statistical analyses, potentially
allowing more robust multivariate analyses of factors associated
with fatigue severity. On the minus side, however, a skewed
distribution, with a large majority of cases reflecting
mild fatigue, or even possibly, fatigue that is not "pathologic,"
could complicate the interpretation of the data or lead
to questions about the generalizability of the results.