Find the sum of the rational expressions and simplify. Which of the following options correctly represents the simplified expression? (x)/(x+3)+(y)/(y+3)

A) (2x+2y)/(2x+2y+6)
B) (x+y)/(x+y+6)
C) (x+y)/(2x+2y+6)
D) (2x+y)/(2x+y+6)