Albinism is a genetic mutation that results in some animals being born without the enzyme that produces the pigment for skin and eye color. All BUT one statement is a possible explanation for this mutation. Which is NOT an explanation?

Albinism in humans is a congenital disorder characterized by the complete or partial absence of pigment in the skin, hair and eyes. Albinism is associated with a number of vision defects, such as photophobia, nystagmus, and amblyopia. Lack of skin pigmentation makes for more susceptibility to sunburn and skin cancers. In rare cases such as Chédiak-Higashi syndrome, albinism may be associated with deficiencies in the transportation of melanin granules. This also affects essential granules present in immune cells leading to increased susceptibility to infection.

Albinism results from inheritance of recessive gene alleles and is known to affect all vertebrates, including humans. It is due to absence or defect of tyrosinase, a copper-containing enzyme involved in the production of melanin. It is the opposite of melanism. Unlike humans, other animals have multiple pigments and for these, albinism is considered to be a hereditary condition characterised by the absence of melanin in particular, in the eyes, skin, hair, scales, feathers or cuticle. While an organism with complete absence of melanin is called an albino an organism with only a diminished amount of melanin is described as leucistic or albinoid. The term is from the Latin albus, "white".

Whichever choice is not described in the above passage is not an explanation.