Coupling linkage is also known as:
Repulsion linkage
Dominant linkage
Complete linkage
Cis linkage
Coupling linkage is a type of linkage between two genes on the same chromosome where the two alleles of each gene are present on the same chromosome. This is also known as cis linkage, where the two linked genes are present on the same homologous chromosome. When two genes are in coupling, they tend to be inherited together, unless there is a recombination event between them during meiosis. This is because they are present on the same chromosome and are physically close to each other. In contrast, repulsion linkage, also known as trans linkage, refers to two genes on the same chromosome, but each allele is present on a different homologous chromosome.
Option 4 is the correct answer.