How to answer to pop-ups

How should I answer to an alert like this? The ip address is in my network, but I don’t know whether it is a web browser, or an application or what? Does Comodo automatically select the correct option? How do I know if it is safe?

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if you are not using port 139 I would block it,

Port 139 NetBIOS

NetBIOS Session (TCP), Windows File and Printer Sharing

This is the single most dangerous port on the Internet. All "File and Printer Sharing" on a Windows machine runs over this port. About 10% of all users on the Internet leave their hard disks exposed on this port. This is the first port hackers want to connect to, and the port that firewalls block. 

you can also disable this by going to control panel, manage network connection. Right click on the local are connection (be it wired or wireless) and selecting properties. Uncheck “File and printer sharing for microsoft networks”, hit okay and this closes that port permanently.

I recognize the ip address as my wife’s computer, and I do have file and printer sharing enabled. I would like to leave file and printer sharing enabled, so now what?

Then just allow it (also check remember), basically her computer wants to talk to yours and comodo is doing it’s job by letting you know.