The table below shows the quantity of yams (in kg) produced by four yam producing states in Nigeria between 1995 and 1998; 

Quantity of yams in kilograms produced between 1995 and 1998

State	1995	1996	1997	1998
A B C D	300,000 500,000 600,000 700,000	400,000 500,000 700,000 600,000	500,000 600,000 800,000 500,000	600,000 700,000 800,000 400,000

Use the table to answer the following questions

(a) Calculate the total quantity of yams produced in the four states during the period (1995-1998)

(b) Construct a pie-chart to show the quantity of yarns produced by each state in 1998

(c) State two advantages of a pie-chart