Question

A paleontologist measures the ratio of carbon-14 to carbon-12 in a fossil skull found at a site. What technique is he using and for what purpose?
(Points : 2)
using alpha emission to determine the structure of the skull

using radioactive decay to determine the structure of the skull

using gamma emissions to date the skull

using radioactive decay to date the skull <--- thats what i want to say the answer is but im not sure if im right