Lane 1 in the Following Southern Blot Contains a Sample

Lane 1 in the following Southern blot contains a sample from a normal control, and lane 2 contains a sample from a patient.The probe is based on the cDNA of a gene.Which type of mutation is most likely, on the basis of these data?

A) Point mutation changing an amino acid coding codon into a stop codon.
B) Insertion of an Alu sequence.
C) Duplication of three exons.
D) Deletion of the entire gene.
E) Deletion of part of one exon.