You technically shouldn't postpone the counterclaim and only introduce it in a conclusion or ending point. That wouldn't be effective let alone a good choice if you were supposedly suppose to make someone actually grasp your argument. Besides... A counterclaim is usually presented in the 2 - 3 paragraph and mentioned within a thesis. D is out.
There are various ways to present a counterclaim... I am unsure of what the correct answer would be. I am leaning towards A or B... It's a counterclaim after all.