Which of the following characteristics makes chlorobutanol a preferred preservative?

Chlorobutanol is preferred as a preservative primarily because it is stable at room temperature. This stability means that it can effectively maintain its efficacy without the need for special storage conditions, making it convenient for use in various formulations. Stability at room temperature ensures a longer shelf life for products containing chlorobutanol, which is particularly important in maintaining the integrity and effectiveness of medications or cosmetic products over time.

In contrast, while being inexpensive, having a low incidence of allergic reactions, or requiring refrigeration may also influence a preservative's selection, they do not offer the same level of reliability and convenience as stability at room temperature. A preservative that needs to be refrigerated would limit its applicability and convenience for both manufacturers and consumers. Therefore, the characteristic of stability at room temperature solidifies chlorobutanol's status as a preferred choice in preserving formulations.