Sentence Correction

In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre,which more than doubled the country's size and that brought its western border within reach of the Pacific Ocean.
A. In the Louisiana Purchase of 1803, the United States acquired 828,000 square miles for about four cents an acre, which more than doubled the country's size and that brought
B. For about four cents an acre the United States acquired, in the Louisiana Purchase of 1803, 828,000 square miles, more than doubling the country's size and it brought
C. With the Louisiana Purchase in 1803, the United States acquired 828,000 square miles for about four cents an acre, more than doubling its size and bringing
D. The United States, in the Louisiana Purchase of 1803, for about four cents an acre, acquired 828,000 square miles, more than doubling the country's size, bringing
E. Acquiring 828,000 square miles in the Louisiana Purchase of 1803, the United States bought it for about four cents an acre, more than doubling the country's size and bringing

Ans: C
It has : more than doubling its size and bringing
and D is wrong: as it has no and before bringing

As per MGMAT SC guide it says that ',and' can be used for a list of item or for two complete sentences. For the above question it is a list of items so its ok use either A and B or A, and B
So I understand why C is correct and D is wrong


For the below question answer choice is C:
In (C choice) sentence there is no ' and' for the correct choice C but is still right.
Should there not be 'and' before 'broadening ....' Can someone help what I am missing to understand

Also there is ',and ' before eventually , should it not be just 'and' without a comma

The hognose snake puts on an impressive bluff.... but it has no dangerous fangs and no venom, and eventually, if its pursuer is not cowed by the performance, will fall over and play dead.

The hognose snake puts on an impressive bluff, hissing and rearing back, broadens the flesh behind its head the way a cobra does, feigning repeated strikes, but, having no dangerous fangs and no venom, eventually, if its pursuer is not cowed by the performance, will fall over and play dead.
A. broadens the flesh behind its head the way a cobra does, feigning repeated strikes, but, having no dangerous fangs and no venom,
B. broadens the flesh behind its head the way a cobra does and feigns repeated strikes, but with no dangerous fangs and no venom,
C. broadening the flesh behind its head the way a cobra does and feigning repeated strikes, but it has no dangerous fangs and no venom, and
D. broadening the flesh behind its head the way a cobra does and feigns repeated strikes, but with no dangerous fangs and no venom, and
E. broadening the flesh behind its head the way a cobra does, feigning repeated strikes, but with no dangerous fangs and no venom, and

Ans: C But has no 'and' after The hognose snake puts on an impressive bluff, hissing and rearing back,