Which of the following is part of the definition of a Currency Transaction Report (CTR)?

A Currency Transaction Report (CTR) is specifically defined as a report that financial institutions are required to file for cash transactions that exceed $10,000. This requirement is intended to aid in the monitoring of potentially suspicious activity and to comply with regulations aimed at preventing money laundering and other financial crimes. The emphasis on cash transactions is crucial, as it relates to the movement of physical currency and helps track large movements of cash which can indicate illicit activities.

The other options do not align with the definition of a CTR. For example, reports filed for checks or online banking transactions do not fall under the CTR guidelines, as these transactions involve different methods of payment and are not solely focused on cash transactions. Additionally, a report for all transactions conducted within a day does not meet the specific criteria that focus on cash transactions over the $10,000 threshold. Thus, the correct choice highlights the salient point that CTRs are specifically for cash-based transactions that meet the specified monetary limit.