Which locations are deemed hazardous when working in confined spaces?

In the context of working in confined spaces, all of the listed locations are considered hazardous due to the specific conditions they may present. Confined spaces, such as storage bins, silos, and tanks, can pose serious risks because they often restrict airflow, may contain hazardous atmospheres, and can trap workers in dangerous situations.

Storage bins can harbor dust, flammable materials, or chemicals that create respiratory hazards. Silos can contain grain or other particulate matter that may produce dust explosions or lead to suffocation if not properly ventilated. Tanks, depending on their contents, can present a myriad of hazards, including the presence of toxic substances or the risk of drowning in liquids.

Because these spaces are typically enclosed and do not allow for easy entry and exit, the potential for hazardous conditions is exacerbated. All of these factors contribute to the classification of storage bins, silos, and tanks as hazardous locations when working in confined spaces, thus making 'all of these' the correct choice.