Handout Master option has the following use:

Concept

In Microsoft PowerPoint, a Master is a top-level template that stores the default layout, placeholders and formatting that flow down to every related output. The Handout Master specifically governs how the slides of a presentation appear when they are printed as audience handouts — that is, the printed page that shows reduced (thumbnail) copies of the slides together with shared page elements.

What the Handout Master controls

Because the Handout Master defines the whole printed-handout page, it lets you set every part of that page in one place:

• It produces the printable handout pages you give to an audience, so the presentation can be distributed on paper.

• It carries page-level placeholders such as a header, a footer, the date/time and a page number that then appear on each handout page.

• It arranges the slides as small (miniature) thumbnails laid out on the page — 1, 2, 3, 4, 6 or 9 slides per sheet.

Conclusion

Each of the three listed uses describes a genuine function of the Handout Master — preparing distributable handouts, setting header/footer/date-time, and laying out miniature slides on paper. Since no single option is exclusive and all three are correct, the option that covers all of them is the right choice.