A correlation, strong or moderate, does not indicate causation.
A negative correlation means that when a variable increase the other decrease.
Discovering lurking variables is no that easy, you are supposed to understand the data and the variables that can affect the process.
The fact that the correlation is moderate makes is difficult to tell if the relation is meaninful to indicate a lurking variable.
What could affet the purcahses of a computer inversely than it affects the purchases of microwaves. It could be a temporary thing or a situation of a particular region.
You should not tell that the correlation is most likely a coincidence because while there is a moderate correlation you have to explore until finding the lurking variables or that the correlation dissapears.
So the right answer is the first option. The correlation is most likely due to a lurking variable.
