If a sign has a white background, it is most likely .

Safety instructions

Explanation:

Safety measures and instructions for safety everything has white back ground board. This increases the visibility of the board and has clarity for the viewers. These sign boards try to give information of things to be done to be safe.

Also the white background boards have letters in black that will increase the readability. These signboards can be seen in streets, highway, railways, airplanes etc. These signboards help to prevent unnecessary accidents and it is precautionary measure.

what do you mean.why did u repeat the question.

if it is for a job, then you should learn everything you can about the job, like what does it involve, what qualification is required and how you are the right person for that job. dress appropriately for the interview. get plenty of rest the night before. good luck!