Answer:
This one's pretty simple. Mc and Pr aren't even actual elements. The symbol for Mercury is Hg, Mn is Manganese.
The correct answer would be D
2 moles of HgO decomposing (essentially splitting apart into their original elements) into 2 moles of Hg and 1 mole of O2 (Oxygen is a diatomic molecule meaning it always has 2 of itself attached, and O2 is always in its gaseous form)
