Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.

It's up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as compiler cares you're okay.

They all must be public, and are therefore public by default.

An out parameter allows an instance of a parameter object to be made inside a method. Reference parameters must be initialised but out gives a reference to an uninstanciated object. C#, C-Sharp

The parameters to your script can be passed as -n 15 -x 20. Inside the script, you can iterate through the getopts array as while getopts n:x option, and the variable $option contains the value of the entered option.

It's possible if these variables are final.