In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Problem: the total circumference of two circles is 49 . if the first circle has a circumference that is exactly twice the circumference of the second circle , then what is the approximate sum of their two radii ?
Options: a ) 7.8 , b ) 6.0 , c ) 6.7 , d ) 9.7 , e ) 18.0
a