human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: Year, Road Opened, Road Closed, Freight Carried s Tonne, Super B Capacity Reached [ citation needed ], Number of Truck Loads North
###Question: What is the smallest amount of freight carried on the road that closed on March 31 and reached super B capacity on February 17 after 2011?
gpt
SELECT MIN Freight Carried s Tonne FROM table WHERE Road Closed = march 31 AND Super B Capacity Reached [ citation needed ] = february 17 AND Year > 2011