The circumference of a circle with a radius of 2 meters is 4 ; the circumference of circle with a radius of 8 meters is 16; and the circumference of a circle with a radius of 10 meters is 20. Which of the following gives the circumference , c, of a circle with a radius or r unit? A.C= ½ r + N B. C=2r + n C . C= 1/2nr D. C = 2nr