In bitcoin network will there be a path from every node to every other node?
The bitcoin network is only as connected as each node wants to be. The protocol is designed in such a way as to incentivize being connected to the network, so in practice, almost every full node is connected to a lot of other nodes and hence, there's at least a very good chance of a short path between any two nodes.

However, that's not to say that every node is connected. It is entirely possible to run a full node that's not connected, like you seem to have done. In your case, it seems C does not have any peers, so C's mined block won't get to anyone else.

Run this command to see which peers it has:

$ bitcoin-cli getpeerinfo


You'll want to add connections this way:

$ bitcoin-cli addnode &lt;node ip and port&gt; add