Researcher: This fall I returned to a research site to recover the armadillos I had tagged there the previous spring. Since a large majority of the armadillos I recaptured were found within a few hundred yards of the location of their tagging last spring, I concluded that armadillos do not move rapidly into new territories. Which one of the following is an assumption required by the researcher's argument?
A: A large majority of the recaptured armadillos did not move to a new territory in the intervening summer and then move back to the old territory by the fall.
B: Predators did not kill any of the armadillos that had been tagged the previous spring.
C: The tags identifying the armadillos cannot be removed by the armadillos, either by accident or deliberately.
D: Of the armadillos living in the area of the tagging site last spring, few were able to avoid being tagged by the researcher.
Choose A, B, C or D as your solution.
A