Explanation:

Explain 

The presence of the preposition ‘between’ in the statement II clearly indicates that the starter has to connect to statement II that would be followed by statement I. Further, we can infer from the statements given that both the statements are contradictory in nature. Kindly refer to the phrases taken as reference below.
 
Reference:
 
“conflict-free” in statement II and “subject to conflicting interpretations” in statement I.
 
Applying the elimination technique, let’s check the relevance of each of the options one by one.
 
Possibility 1:
 
While the border areas between the two countries have remained conflict-free, the Line of Actual Control continues to be subject to conflicting interpretations by both India and China and the scene of intermittent transgression.
 
We can observe that the above synthesis is both grammatically and contextually correct. This eliminates option C.
 
Possibility 2:
 
To keep the border areas between the two countries have remained conflict-free, the Line of Actual Control continues to be subject to conflicting interpretations by both India and China and the scene of intermittent transgression.
 
The above synthesis is grammatically incorrect and thus the phrase/connector can’t be accepted as a valid one. Hence, option B and E also get eliminated.

Possibility 3:
 
Despite the border areas between the two countries have remained conflict-free, the Line of Actual Control continues to be subject to conflicting interpretations by both India and China and the scene of intermittent transgression.
 
The above synthesis is grammatically correct and keeps the context meaningful.
 
Clearly, option D is the correct answer.