There are 12 months in a yr so 12/3=4 then 1/3x4=4/3 so 1ft and 1/3 erode each yr. C is the correct answer<span />
Answer:
y = 20
Step-by-step explanation:

If this is right, then please make it the brainliest.
The answer to your question would be B.
I hope this helped:D