What is the purpose of the startup configuration file on a Cisco router?

What is the purpose of the startup configuration file on a Cisco router?

• to facilitate the basic operation of the hardware components of a device
• to contain the configuration commands that the router IOS is currently using
• to provide a limited backup version of the IOS, in case the router cannot load the full featured IOS
• to contain the commands that are used to initially configure a router on startup
  

  Explanation: The startup configuration file is stored in NVRAM and contains the commands needed to initially configure a router. It also creates the running configuration file that is stored in in RAM.