Ms. Zhou Mr. Li is humorous. They are popular among us students.
A:Both; and
B:Neither; nor
C:Either; or
D:Not only; but also
已知色盲基因在X染色体上,现有一色盲男孩,其父母、祖父母、外祖父母色觉均正常.这个男孩的色盲基因来自( )