Explanation:

Explain 

In the above statements, while statement II affirms an occurrence of an event, statement I re-affirms it in a bit elaborative manner.
 
Applying the elimination technique, let’s check the relevance of each of the options one by one.
 
Possibility 1:
 
As long as the long queues in the outpatient clinics at medical colleges and general hospitals are often the first indicator of the beginning of the epidemic season in Kerala, usually, dengue cases begin to peak with the arrival of the southwest monsoon.
 
Clearly, the above synthesis is contextually flawed and obstructs the flow of the sentence. The synthesis is hence invalid and thus eliminates option C.
 
Possibility 2:
 
Though, usually, dengue cases begin to peak with the arrival of the southwest monsoon, the long queues in the outpatient clinics at medical colleges and general hospitals are often the first indicator of the beginning of the epidemic season in Kerala.
 
Usage of though in a clause is generally followed by a contradiction whereas the synthesis above doesn’t indicate a contradiction at all.
 
Clearly, the phrase/connector ‘b’ also stays invalid. Options B and D also get eliminated.
 
Possibility 3:
 
Surpassing the beginning of the epidemic season in Kerala,the long queues in the outpatient clinics at medical colleges and general hospitals are often the first indicator, usually, dengue cases begin to peak with the arrival of the southwest monsoon.
 
As we can observe that the synthesis above doesn’t make a meaningful sentence either, we can conclude that none of the constructions stays logical here.

Option E is hence the correct answer.