What is the value of the expression 1/{1+1/(1+1/4)}?

A 9/5

B 1/2

C 3

D 5/9

Correct Answer: Option D

1/ { 1 + 1 / ( 1 + 1/4 ) } = 1/ { 1+ 1 / 5/4 } = 1/ ( 1 + 4/5 ) = 1/ ( 5+4/5 ) = 1/ ( 5+4 / 5 ) = 5/9