Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_13999 ( "City" text, "System" text, "Category" text, "Daily ridership" real, "As of" text, "Opened" real, "Stations" text )

### Question ###
Which Opened has a System of c-train, and a Daily ridership smaller than 269,600?

### Accurate SQL ###

SELECT MAX("Opened") FROM table_13999 WHERE "System" = 'c-train' AND "Daily ridership" < '269,600'