I think the correct answer is E.
The statement “although some burglars will undoubtedly escape” is not the main conclusion.
It is a concession.
The author is basically saying:
“Yes, some burglars may escape...”
BUT
“a large percentage of burglars will still be caught.”
So the statement accepts a small opposing point without damaging the overall conclusion.
That is exactly what option E describes.
Why the others do not fit:
(A) Incorrect.
The statement is not evidence supporting the conclusion. The actual support is:
“70% of criminals are caught” + “burglars are criminals.”
(B) Incorrect.
It is not the conclusion of a separate argument. Nothing is being proven there.
(C) Incorrect.
It is not giving an example. It is making a concession.
(D) Incorrect.
The opposing position was:
“burglars run almost no risk of being caught.”
But the statement says only:
“some burglars will escape.”
That is much weaker and not the same claim.
(E) Correct.
The author concedes that some burglars escape, but says this does not weaken the main conclusion that many burglars are eventually caught.
So the role of that statement is to acknowledge a minor point while still defending the overall argument.
Answer: E