Select the correct answer.
The images show two different types of Galapagos tortoises that scientists believe descended from the same species. The first type (left) are found on islands that have high vegetation and few grasses. The second type (right) are found on an island that has large amounts of grasses and low-lying shrubs. What explains the type of turtle found on the islands with high vegetation?

The image shows two different types of Galapagos tortoises. The tortoise on the left has a vegetarian and few grasses. The tortoise on the right has a large number of grasses and low-lying shrubs.

A.
The environment triggered a gene mutation in neck length in order to help the turtle survive.
B.
Mutations are random, so it is by chance that turtles with longer necks live on these islands.
C.
Turtles with genes for long necks had a better chance of surviving to reach reproductive age.
D.
Turtles with short necks completely lacked adaptations for finding food, so they died off.