Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Measuring tree diameter at breast height (DBH) is standard practice in forest inventories.
Reason (R) : DBH provides consistent reference point for all trees, allowing for rough calculation of basal area and volume.
In the light of the above statements, choose the most appropriate answer from the options given below :