The problem is that no results are showing up in the command window. After I select my first & second points, the command window asks me to enter an option—see attached image. When I add "D" in the command window it asks me to enter the first point, second point, and the process begins again with no measurement ever being revealed.

It's strange that I've not seen the ? previously and that I've successfully completed inquiries prior to seeing the ?. I'm wondering if I unknowingly turned something on or off or...who knows.

I'm new to the Mac version, but I'm fairly familiar with AutoCAD in windows. 

Thanks for any help you can provide.