Answer:
b. forward mutation, suppressor mutation
Explanation:
When the nucleotide sequence of an organism is altered, it is called as mutation. It can be caused by DNA damage or replication errors. In forward mutation, the wild type allele is converted to a mutant version such that the gene product is non functional or its not produced at all. Suppressor mutation is the second mutation which reverses the phenotypic effects of the previous mutation. This process is called as synthetic rescue.
Since here gene X was converted into a mutant form by the mutation, it had undergone forward mutation. When gene Y was mutated, the function of gene X was restored which ultimately also restored the phenotype hence it is an example of suppressor mutation.
What are the options? I can’t see well
