Which of the following types of variables would have a true zero point?

A ratio scale has a true zero point that denotes complete absence of the quantity.

Weight, height and income are ratio variables where zero means none.

Nominal variables only name categories and carry no numerical zero.

Ordinal variables rank categories but lack equal intervals or a real zero.

Interval variables have equal intervals but an arbitrary zero, like Celsius temperature.

Only ratio scales permit meaningful ratios such as twice as much.