The correct answer is - A. Papua New Guinea.
The biggest possibility and also logically, that a mining company will have operation in Oceania, from the suggested options, is in Papua New Guinea. The reason for that is that Papua New Guinea is an island that is rich in gold. In fact, most of the economy of the country is based around the gold mining, with only one exception where there's gold and copper mining. The opportunity to mine gold at a place where there's an abundance of it, and also where the labor-force is very cheap, seems like a perfect situation, so a mining company will naturally be attracted to it in order to make big profit.