Which of the following characters in a shell prompt indicates the shell is running with root privileges?

The '!' character is commonly used in shell commands to denote history expansion or to reference previous commands but does not indicate user privileges. It is not a character associated with indicating root access or user permissions in the shell prompt.

The '*' character does not have a standard meaning in shell prompts related to user privileges. It is often used as a wildcard in command-line operations to represent any number of characters in file names or commands, but it does not convey information about the user's access level.

The '$' character is the standard prompt indicator for regular users, signifying a non-root session. When users see this symbol, it means they are operating under normal user permissions, with restricted access compared to root privileges.

The '%' character is sometimes used in shell prompts, particularly in csh or tcsh, but it does not indicate root access. Instead, it typically represents a user with limited privileges or specific configurations in certain shell environments.