Challenge 1: A Single-Application Tutorial Recording — Solution Walkthrough

The best fit:

Window Capture.

Why, per this chapter's own material:

Window Capture captures one specific application window only, showing
nothing else from the desktop at all — no other windows, no
notifications, no general clutter. That's precisely what a tutorial
needing to show only one specific application requires: a clean,
focused recording containing exactly the intended content and nothing
else.

Why Display Capture would be a worse choice here:

Per this chapter's own material, Display Capture shows the entire
monitor — genuinely "what you see is what you get," including any
other windows, notifications, or desktop clutter that happens to be
visible at the time. For a tutorial specifically needing to show only
one application, Display Capture risks accidentally revealing
unrelated windows, a notification popping up mid-recording, or other
distracting content the viewer was never meant to see.

WHY THIS WORKS AS AN ANSWER
------------------------------
This exercise is a direct, practical application of this chapter's own
Window-Capture-vs-Display-Capture distinction to the exact use case
(a clean single-app tutorial) the chapter names as Window Capture's
own strongest fit.