Bears are sometimes viewed as vicious predators, but they are actually omnivores, not strict carnivores, and their diet is simple, consisting mostly of fruits, nuts and berries, eggs, and grub worms, and salmon occasionally.
Here's my take on the subject, if I'm understanding anything wrong please correct me:
The comma + connector (i.e. FANBOYS) joins two independent clauses together. Here, the independent clauses in this sentence are:
1. Bears are sometimes viewed as vicious predators.
2. They are actually omnivores, not strict carnivores.
3. Their diet is simple, consisting mostly of fruits, nuts and berries, eggs, and grub worms.
4. Salmon occasionally.
The last independent clause is the underlined portion and is incorrect because 1) it cannot function as an independent clause because there is no verb associated with the subject and 2) it doesn't present any logical or complete meaning. Therefore A is incorrect. Connector Error.
A. and salmon occasionally Incorrect (see reason above).
B. and salmon is occasionally To me, this is still a connector error because it still doesn't present any logical or complete meaning. The salmon is occasionally what? Eliminate.
C. with salmon as occasional For me, the connector error is gone since the "with" changes the independent clause to a prepositional phrase. Now, "with salmon as occasional" seems to modify "their diet is simple". However, this is an incorrect use of "as". Here, "as" cannot present the function of salmon ("salmon as occasional"? doesn't make sense), and no other uses of "as" makes sense in this context. Comparison Error. Eliminate.
D. salmon an occasional meal This to me is a meaning error because it doesn't present any logical or complete meaning (again). "Salmon an occasional meal" doesn't have any logical meaning in this context. Eliminate.
E. with salmon as an occasional meal Here, the use of "as" is correct: it's presenting the function or role of salmon in the bears' diet, i.e. "an occasional meal". The preposition "with" links this prepositional phrase to "their diet is simple", providing further information in regards to the bears' diet. Correct answer choice.
If anyone can please correct/add to my understanding that'd be great!