The key ethical issues in data mining from the provided options are:
- People may not be aware that their personal information is being gathered.
- People have not consented to the collection or use of the data.
- People do not know how the data will be used.
The option "People want data to be collected quickly" is not an ethical issue in data mining.
For the question regarding the company’s sales in 2012, without a graph provided, I cannot definitively say when the company will most likely have the least sales. Please check the graph for the month where sales appear to be the lowest.