Two normal parents have five children, four normal and one albino. what are the most likely genotypes of the parents?

If the child has albino but neither of his or her parent shows this phenotype, it means that albino is controlled by a recessive gene. Both parents must be heterozygous then.

Let R be the dominant (normal) allele, and r be the recessive (albino) allele, so the genotypes of the parents must be Rr and Rr.

Both must be heterozygous, only this cross can form both normal children and albino children when they do not show this phenotype.

C. gemstones they are the only non metallic mineral from the list.