I would go with choice C) Pollution or the 3rd option.
Answer:
A gene mutation can be described as errors in the nucleotide sequence of a gene due to errors in the DNA replication process or due to any mutagen. On the other hand, a chromosomal mutation can be described as a change in the structure of a DNA or changes in the number of chromosomes.
A gene mutation occurs in a single gene whereas a chromosomal mutation will affect many genes. Hence, gene mutations will be comparatively less lethal than chromosomal mutations.
Example of gene mutation: Sickle cell anemia
Example of chromosomal mutation: Down's Syndrome
The correct answer to this question is:
“The prediction is useful because it explains what observations will be made if a hypothesis is true.”