Final answer:
The number of candidates in a primary election for mayor, city treasurer, and attorney varies and depends on the specific election.
Step-by-step explanation:
In a primary election, the number of candidates for mayor, city treasurer, and attorney can vary. It depends on the specific election and the number of individuals running for each position. Without more information about the specific election in question, it is not possible to determine the exact number of candidates. However, the options provided in the question are 10, 11, 12, and 13. So, the answer would be one of those options, depending on the specific election.