What is a content delivery network $($CDN$)?$

Question $1$ options:

$1)$

A network of servers that deliver web content to users based on their location and performance

$2)$

A network of computers that share web content among themselves for faster access

$3)$

A network of devices that connect to the internet and request web content from servers

$4)$

A network of cables that transmit web content from one place to another