What must property owners/lessees do when premises are not safe?

When property owners or lessees discover that their premises are not safe, they have a legal duty to take reasonable actions to prevent harm to others. This includes the responsibility to warn of hidden dangers that may not be immediately apparent to those on the property.

The rationale behind this obligation lies in the principle of premises liability, which holds that property owners must ensure that their property does not pose risks to users. If a danger exists that isn't clear to a reasonable person, failing to warn can lead to legal liabilities if someone gets injured as a result. Thus, option C correctly highlights this responsibility to inform individuals of risks that are not visible, encapsulating the essence of property owners’ duties.

In contrast to this, simply closing the premises immediately might not always be feasible or necessary, depending on the severity of the hazards present. Renting to responsible tenants is part of good management but does not directly address safety issues already present on the property. Raising rent to cover expenses may be a business decision, but it does not mitigate the current unsafe conditions or address the legal obligations concerning premises safety.