Answer:
b.) pressing F12, clicking on the link in the Console panel, and reviewing the code in Sources panel
Step-by-step explanation:
If an error pops up, one can always see it by pressing the F12.
After that, a Console panel is shown with the information(and only the information) about type of error.
Inside that information there is always a clickable link which leads one into the Sources panel.
There the mistake can be red, and alternatively corrected.