Which of these would most likely result in a change to a current classification of an organism?

Since you did not give choice to your question, I'll give you a brief information relative to the topic above.
An analysis of the DNA sequence of an organism  will most probably  result in a change to a current classification of an organism. 
>>>DNA analysis is one of the new reasons why organisms/species are being re-evaluated . Basic genetic analysis information can change our ideas of how closely two organisms/species are closely related thus, their classification can change.