riskietech
We see following four lists in Qn:
P--> the patterns of dynastic rise and fall,
Q--> intermittent aggression from northern aliens,
R--> varying degrees of openness to outside cultural influences
S--> the dynamics of stability and social harmony
List P & Q are noun clauses that needs to be parallel
List R & S are adjective clauses that needs to be parallel
Now let us check each of the options:
A. Among the important themes that characterize Chinese history are the patterns of dynastic rise and fall, intermittent aggression from northern aliens, and varying degrees of openness to outside cultural influences and the dynamics of stability and social harmony
Incorrect, P,Q,R & S cannot be parallel simultaneously as they belong to different clause category.
B. Among the important themes that characterize Chinese history are the patterns of dynastic rise and fall, and intermittent aggression from northern aliens, together with varying degrees of openness to outside cultural influences and the dynamics of stability and social harmony
Correct. P is parallel to Q, [connector] R is parallel to S
C. The important themes that characterize Chinese history are the patterns of dynastic rise and fall, intermittent aggression from northern aliens, along with varying degrees of openness to outside cultural influences and the dynamics of stability and social harmony
Incorrect. Here Q follows P but is not separated by parallel marker "and". R is parallel to S.
D. Among the important themes of Chinese history are the patterns of dynastic rise and fall, intermittent aggression from northern aliens, varying degrees of openness to outside cultural influences and the dynamics of stability and social harmony that characterize its history
Incorrect. Same as A. Also the phrase "the dynamics of stability and social harmony that characterize its history" changes the intended meaning of "themes that characterize its history"
E. The important theme that characterizes Chinese history is the pattern of dynastic rise and fall, intermittent aggression from northern aliens, along with varying degrees of openness to outside cultural influences and the dynamics of stability and social harmony
Incorrect. Same as C
Answer: B
Hope this helps!
In option B
A,and B is a wrong usage
correct usage is A,B,and C
Additionally,punctuation is not tested on this exam.
don't worry about whether a comma should be placed in front of "and". that's almost entirely a stylistic issue, and thus beyond the scope of this exam.