Insurable risks are characterized as being:

Insurable risks are defined as risks that can be quantified and managed, allowing insurance companies to create policies based on the likelihood of a loss occurring and the potential financial impact of that loss. The correct answer highlights that insurable risks are unexpected but can be calculated based on statistical data and historical patterns.

By being unexpected, these risks do not follow a predictable pattern; they could occur at any time and may surprise the insured parties. However, since they are calculable, insurers can use actuarial science to analyze data, set premiums, and determine appropriate coverage levels. This balance between uncertainty and the ability to estimate likelihood makes these risks insurable.

In contrast, other characteristics such as being abstract, volatile, intangible, or substantial would not provide the necessary framework for insurability, as they either lack a basis in quantifiable data or imply risks that cannot be adequately managed or measured, making it difficult for insurance companies to operate sustainably.