Find out the organism with highest life span -
The period from birth to the natural death of an organism represents its life span.
Galápagos tortoises are noted to live over 150 years, but an Aldabra giant tortoise named Adwaita may have lived an estimated 255 years. In general, most tortoise species can live upto 200 years.
Life span of horse is around 60 years, fruitfly is approximately 2 months and for dog is 20-30 years.
So the highest life span among the given options is of "Tortoise"