Correct answer is (B), It depicts 6 oxygen atoms.
You have to "distribute" the 2. N has 2 and O has (3x2) which is 6.
Letter A is incorrect because the "C" is part of "Cu" which is copper.
Letter C in incorrect because it depicts 6 oxygen atoms instead of 9.
Letter D is incorrect because it does not contain 3 atoms of copper, it contains 3 moles of copper. big difference
