Answer:
a. Dendrochronology
Explanation:
Dendrochronology is defined as the science used by archaeologists to observe environmental changes or conditions of a period by counting the rings in trees and observing the space between the rings.
Dendrochronology is very useful to determine the precise age of trees and the trees which are recently undergoing radiocarbon dating.
Hence, the correct answer is "a. Dendrochronology".
