A radioactive probe is generated using the actin gene from yeast.This probe is used in a Southern blot analysis of EcoRI digested genomic DNA from the ciliated protozoan Tetrahymena thermophila.The autoradiogram shows a single-labeled band of 4 kb in size.This means that the Tetrahymena actin gene is:
A)4 kb in size. B)the same size as the yeast gene. C)present in one copy in the genome. D)present in four copies in the genome. E)identical in sequence with the yeast gene.