Which of the following would cause a TCP$/$IP connectivity issue between two routers?

answer

Both routers have an IP address of $192\mathrm{.}168\mathrm{.}1\mathrm{.}100.$

The routers are configured to use HDLC encapsulation.

Both routers have a subnet mask of $255\mathrm{.}255\mathrm{.}255\mathrm{.}0.$

Router $1$ has an IP address of $192\mathrm{.}168\mathrm{.}1\mathrm{.}100,$ and Router $2$ has an IP address of $192\mathrm{.}168\mathrm{.}1\mathrm{.}101.$