How are the terms homozygous and heterozygous different?

Homozygous describes having two of the same allele for a trait, and heterozygous describes having two different alleles for a trait.
Homozygous describes having recessive alleles for a trait, and heterozygous describes having dominant alleles for a trait.
Heterozygous describes having two of the same allele for a trait, and homozygous describes having two different alleles for a trait.
Homozygous describes having dominant alleles for a trait, and heterozygous describes having recessive alleles for a trait.

The correct answer is:

Homozygous describes having two of the same allele for a trait, and heterozygous describes having two different alleles for a trait.