The classification can be revised based on DNA studying.
Option A.
Explanation:
The DNA or the Deoxyribonucleic acid is the complex molecule that's present in every cells of an organism and it is the molecule for storing the genetic information of an organism. The DNA contains the genes that are transferred from one organism to its offsprings by means of sexual reproduction.
In case of Red pandas, the detailed study about the genes present in them, along with the genes present in their near relatives and a tally between them gives us the information about the number of similar genes and their positions in chromosomes. So the study of DNA information gives the most chance to study the classification of the Red pandas.
Organisms can be made up of many<em> </em><u>cells</u>, which could be arranged into <u>tissues</u> which can make up<u> organs</u>, organs can be part of a(n)<u> system</u>. These are........i don't really know after this since you didn't give a lot to work with and i'm not even sure if this is right or not lol.