To be meaningful, a measurement should have a: only a unit b: a prefix and a number c: a number and a unit d: only a number

The answer is option C.

Explanation:

There are four estimation scales or sorts of information, ostensible, ordinal, interim and proportion. These are just approaches to arrange diverse sorts of factors. This point is generally talked about with regards to scholastic instructing and less regularly in the "genuine world."A number or amount that records a specifically discernible esteem or execution. All measures have a unit joined to them: inch, centimeter, dollar, liter, and so on. Interestingly, a marker is a backhanded measure or an indicator, for example, a main Indicator of execution.

i'd say that the moon rock is about 2.2 billion years old.

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.