A paratrooper, when asked whether he believed the military objective

Look at his train of thought:
Premises:
Commands the valley, so important in conventional war.
This is not conventional war.

Conclusion: So not important.

This is not a logical conclusion, right? Something that is important in conventional war could also be important in an unconventional one. What can I do to strengthen this conclusion. Is there a missing premise, which, if added could make this argument logical?
If I were to add a premise here 'what is important in a conventional war, is not important in an unconventional one', would the conclusion become valid?

See again:
Premises:
-Commands the valley, so important in conventional war.
-This is not conventional war.
-What is important in a conventional war, is not important in an unconventional one

Conclusion: So not important.

Now it is a valid conclusion. So the argument can be strengthened by adding this premise, this new information. Hence, answer is (E).