From Which command tab is the font size for an axis in a chart change…

The correct answer is Option (1) → Home

The text in a chart element, such as an axis, is formatted like any other text: select the axis (or its text) and use the font size box in the Font group of the Home tab (the Mini toolbar that appears on right-clicking has the same buttons).

Option (2) Insert — Incorrect. The Insert tab is used to insert a chart, not to format its text.

Option (3) Format — Incorrect. The Chart Tools Format tab applies shape styles, WordArt styles and effects to chart elements; the font size is set in the Font group of the Home tab.

Option (4) Design — Incorrect. The Design tab changes the chart type, layout, style and data source.