A Study Was Conducted to Identify a Liver Cell Gene

A study was conducted to identify a liver cell gene (zed) that has a length of 3000 bp.A southern blot was prepared using DNA from the liver cell and a probe made to region 1600-2000 of zed.Analysis of the blot revealed that there are two spots present,one at 3000 and another at 2000.A plausible explanation for this observation is:

A) there is an identical copy of this gene on another chromosome.
B) the gene was cut in two equal portions by a restriction enzyme.
C) there is a another gene with sequence similar to gene zed.
D) both there is an identical copy of this gene on another chromosome and there is a another gene with sequence similar to gene zed are correct.
E) no explanation can be given using the available data.