I don't feel there is any intrinsic value in a store based on where it is headquartered. Whether that means a local business headquartered in a single shop, or a large big box corporation headquartered in an office building.
The things that make a local business valuable are different from what makes a large corporation valuable. Small local businesses get their products from the same sources as large corporations. Unless you mean "locally produced" which you didn't say. In this respect the value that large corporations offer is lower price for the same product, generally smaller businesses will offer better individual service on those products.
For some items there is no significant benefit to the service aspect, so price is the deciding factor (Toilet paper, video games for example). For some items, service is the deciding factor (scuba gear, fish gear, jewelry)
I didn't vote because none of the options take these matters into account. Rather they appear to set up a false dichotomy that Large business = unethical, small business = ethical.