Sentence Correction

According to recent studies comparing the nutritional value of meat from wild animals and meat from domesticated animals, wild animals have less total fat than do livestock fed on grain and more of a kind of fat they think is good for cardiac health.
1. wild animals have less total fat than do livestock fed on grain and more of a kind of fat they think is
2. wild animals have less total fat than livestock fed on grain and more of a kind of fat thought to be
3. wild animals have less total fat than that of livestock fed on grain and have more fat of a kind thought to be
4. total fat of wild animals is less than livestock fed on grain and they have more fat of a kind thought to be
5. total fat is less in wild animals than that of livestock fed on grain and more of their fat is of a kind they think is

In the above question in the non-underlined portion we have “According to recent studies comparing the nutritional value of meat from wild animals and meat from domesticated animals” shouldn’t we have “total fat” immediately after the comma ? Since the sentence talks about comparing nutritional value of meat”
I am not sure why options C & D are wrong.