What indicates that the lug nuts are properly secured?

The indication that the lug nuts are properly secured is demonstrated by the absence of rust, which suggests that they have not loosened over time. When lug nuts are correctly torqued, they will maintain a tight fit. If rust develops around the lug nuts, it could signify movement, which typically occurs when the nuts are not adequately tightened or have come loose.

Recognizing that the lug nuts are secure by checking for rust helps ensure the overall safety and stability of the wheel assembly. It's essential to maintain a keen awareness of visual indicators like rust to avoid any potential issues while driving. The other choices presented do not effectively indicate proper security; in fact, they provide misleading information about lug nut conditions.