Answer 1

counts the times a given string appears in antoher string.

As you are providing an empty string: ‘’, it will look for any emptiness within your string.
Let’s call the empty string “nothing”.
You start your sting with an aperture ‘, between ‘ and the first character there is nothing, same with the first and second caharacter and so on. Between the final
character and the closure ‘ there is nothing again.
In total it would be 4.