Which scientists have contributed to our knowledge of Earth's age?

a-geologists

b-chemists

c-physicists

d-biologists

e-astronomers

A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that have shaped it. Geologists usually engage in studying geology.

Geologists have contributed to our knowledge of Earth's age.

The answer is a geologists because they study the Earth.