A)
twelve hospitals have been investigated by state medical officials,
finding that all twelve consistently break the laws,
many residents work longer than 24 hours straight,
and that more than half the surgical residents work----
Incorrect, because first Investigation has found that hospitals break the laws not state offices or the tweleve hospitals like this sentence implies. Also the many... and that is not parallel. B)
an investigation by state medical officials of twelve hospitals
have found all twelve consistently breaking the laws, that many residents work longer than 24 hours straight, with more than half the surgical residents working----
An investigation does not match with have. SVA error. C)
an investigation of twelve hospitals by state medical officials
has found that all twelve consistently break the laws,
that many residents work longer than 24 hours straight,
and that more than half the surgical residents work---
CORRECT. D) twelve hospitals were investigated by
state medical officials who found all twelve breaking the laws,
with many residents working longer than 24 hours straight,
and more than half the surgical residents work----
Not parallel. the investigation has found, not the state medical officials. E) an investigation by state medical officials has found that,
of twelve hospitals, all twelve consistently break the laws, that many residents work longer than 24 hours straight,
with more than half the surgical residents working---
with is incorrectly used. Also the of twelve hospitals, all twelve sounds words and awkward.