$28$ Which statement is true about Cisco IOS ping indicators?

A combination of $\text{'}\text{'}\text{'}$ and $\text{'}!\text{'}$ indicates that a router along the path did not have a route to the destination address and responded with an ICMP unreachable message.

$\text{'}$U$\text{'}$ may indicate that a router along the path did not contain a route to the destination address and that the ping was unsuccessful.

$\text{'}\text{'}$ indicates that the ping was successful but the response time was longer than normal.

$\text{'}$I$\text{'}$ indicates that the ping was unsuccessful and that the device may have issues finding a DNS server.