GMAT Sentence Correction (SC) | Verbal Diagnostic Test No : 7 – SC Q No:4

We see following four lists inQn:
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