You scored 8 out of 10 (80%).
I disagree on those two I didn't score:
3. He doesn't need to run the program alongside other software
3. You said b - False.
Hard luck. If other software does not need to run alongside the program, a command line interface would be the most appropriate.
I have often several CL interfaces and Windows programs running at the same time. The use of a CL interface does not tell what tasks are running and how much multitasking happens.
5. He wants to run the model railway on a low spec computer
5. You said b - False.
Hard luck. Command line interfaces are good if you only have a low spec computer.
The use of a CL interface does not tell how heavy tasks a PC runs. Any low spec computer with e.g. an ancient Pentium 1, Celeron or similar can run old Windows versions and basic 2D graphical interfaces easily.
Though, that guy may have a Commodore 64. In that case I would accept the scores...