"C" means that the route was learned as it refers to a directly Connected subnet (i.e. those IP addresses are assigned t a network interface on the router itself.
"S" means that the route is a Static route (i.e. an administrator has added a command to the router configuration to hard code that route.)
In Cisco devices, by default, Connected routes have an administrative distance of 0, and Static routes have an administrative distance of 1.
Other things being equal, delivering a packet itself (the route metric - the cost of using this route = the route's administrative distance =0), would be more preferable to passing the packet to another router via a static route (the route metric = the static route's administrative distance = 1, as then the other router needs to perform further operations to deliver the packet).