Which one is the important consequence of geographical isolation?

The correct option is A. Speciation through reproductive isolation.

• The lineage-splitting event that is used to produce two or more separate species is called speciation.
• Natural disasters and natural changes can lead to geographical isolation.
• One of the main consequences of geographical isolation is speciation through reproductive isolation, which is the inability of members of the different populations to mate with the other.
• The isolation that occurs through geographical separation of the population is also known as allopatric speciation.