Answer: 2 is the number of years since it formed
Absolute dating can be defined as an age estimation method which gives the age of the fossil evidence on the basis of studies based upon the chronology of past geological events by examining various physical forms such as strata of sediments or rocks. The absolute dating of the earth material is a measure of how old the material is in years. This method of dating gives an accurate age of the specimen under concern. It is also called as calendar dating or chronometric dating.
On the basis of the above information, the phrase which describes the absolute age of a rock is the number of years since it formed.