Which of the following property sets whether the table borders are collapsed into a single border or separated:?

The correct answer is C.

The border-collapse property sets whether the table borders are collapsed into a single border or separated.

The border property sets the width, style, and color of the border around an element.

The table-border property is not a valid CSS property.

The following is an example of how to use the border-collapse property:

css
table {
border-collapse: collapse;
}

This will cause the borders of the table cells to collapse into a single border.