Answer:
The correct option is D.
Explanation:
In a data set we have three quartiles and the second quartile is known as median.
First quartile Q₁ divides the data set in 1:3. It means
of the data set are less than or equal to Q₁ and
of the data set are more than or equal to Q₁.
Second quartile Q₂ divides the data set in 1:1. It means
of the data values are less than or equal to Q₂ and
of the data values are more than or equal to Q₂.
Third quartile Q₃ divides the data set in 3:1. It means
of the data values are less than or equal to Q₃ and
of the data values are more than or equal to Q₃.
It is given that first quartile of a data set is 2.5. It means
of the data set are less than or equal to 2.5 and
of the data set are more than or equal to 2.5.
Therefore the correct option is D.