Cindy saves $420 each month. Her monthly salary is $2100. What is the ratio of the amount Cindy saves to the amount she earns each month?
A) 1:5←
B) 1:4
C) 2:3
D) 5:1
my answer is D.) 1:5
amount saved to amount earned
$420 to $2100
420/2100=1/5 or 1:5 
is my answer correct