Final answer:
The correct syntax to count the occurrences of a city in a report is =Count([City]). This function counts the non-null occurrences in a dataset.
Step-by-step explanation:
To count the occurrences of a city in a report, the correct syntax would be option a, which is =Count([City]). This is a function commonly used in database reporting tools and software for counting the number of non-null values of a specified field. So, if you want to count how many times a particular city appears in a dataset, you would use this count function.