you must stop and wait behind the stop line
Make sure you learn and understand the sequence of traffic lights. Whatever light appears you will then know what light is going to appear next and be able to take the appropriate action. For example if amber is showing on its own you’ll know that red will appear next, giving you ample time to slow and stop safely.
B you should stop unless turning left
C stop, if you are able to brake safely
D proceed with caution