Answer:
A. In a heterozygous individual, the allele that determines the phenotype
Step-by-step explanation:
The dominant allele completely hides the expression of the recessive allele. This occurs in cases of Autosomal dominant inheritance. Even when both dominant and recessive alleles are present in the genotype, this is the heterozygous state, only the dominant trait will be expressed. Only one dominant allele is enough to express the dominant phenotype.