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_name_43 (background_colour VARCHAR, type_of_sign VARCHAR)

### Question ###
Which color is the background of the mandatory instructions?

### Accurate SQL ###

SELECT background_colour FROM table_name_43 WHERE type_of_sign = "mandatory instructions"