Final answer:
b. Total precipitation on climate graphs is calculated by summing up the precipitation amounts of each month to find the annual total.
Step-by-step explanation:
To calculate the total precipitation in climate graphs, you would use option B) Sum of all monthly precipitation. This means that you add together the precipitation amounts recorded for each month within a given year to find the annual total.
This information helps in understanding the climate patterns of a specific region over a longer period, and can show variations in precipitation that might correlate with seasons or other climatic factors.