Final answer:
The correct answer is that there is no minimum age for opening a bank account as long as a parent or guardian is on a joint account with the minor. The rules can vary depending on the bank and location.
Step-by-step explanation:
The minimum age for opening a bank account can vary depending on the institution and the country. However, commonly there is no set minimum age requirement for owning a bank account as long as a parent or guardian is also on the account. Therefore, the correct answer to the student's question is: Any age if a parent/guardian is on a joint account. Minors, usually individuals under the age of 18, can have a parent or legal guardian as a co-owner of the account, which is typically referred to as a custodial or joint account. Once the minor reaches the age of majority (18 in most jurisdictions), they often have the option to take full control of the account.