A

\[\frac{a+b+d}{a+b+c+d}\]

B

\[\frac{a}{a+b+c+d}\]

C

\[\frac{a+b+d}{a+b+d}\]

D

\[\frac{a+b+c}{c}\]

E

\[\frac{a+b+c}{b+c+d}\]