The boot config command will configure the location of the configuration file. It must be followed by the copy run start command to be effective at next reboot. The syntax of the command is as follows:

boot config device:filename

The parameters of the command are as follows:
* Device : Specifies the device that contains the configuration file.
* Filename : Specifies the name of the configuration file.

The boot buffersize command is incorrect because this command is used to modify the buffer size used to load the IOS image. Moreover, this command no longer functions in IOS 12.4.

The configure command is incorrect because this command is used to enter the global configuration mode.

The service config command is incorrect because this command is used to enable autoloading of configuration files from a network server.