How can I get the "Open in Terminal" Option when I right click in Raspbian OS ?
It opens the terminal in the current directory.
Openbox right-click menu is normally configured in a file called
menu.xml, which is located either in
~/.config/openbox/ or somewhere under
/usr/share/ if you don't have the former file.
Find out what the command syntax is for this "Open in Terminal" option on a system where you have it (I'd expect something like
lxterminal --command=%1), and add this item in the menu of your RPi.