The Account Monitor is the ideal feature for this scenario. It is designed to proactively track key account balances in real time against defined thresholds or tolerances. When an account balance exceeds these tolerances, indicating a potential anomaly like the 30-40% spikes mentioned, the Account Monitor provides immediate visual cues. This allows accountants to identify and investigate significant fluctuations promptly, preventing delays in the reconciliation process. It directly addresses the need for proactive notification of account anomalies.

A. Financial reports with embedded charts: These are reporting tools that show data at a point in time; they are not proactive monitoring or notification systems.

B. Smart View: This is an ad-hoc analysis and reporting tool for Microsoft Office, used for investigation rather than proactive, real-time monitoring.

C. Account Inspector and its charts: This is a drill-down tool used to analyze the composition of an account balance, typically after an issue has been identified by the Account Monitor.

1. Oracle Fusion Cloud Financials Documentation, Using General Ledger, Chapter: Financial Reporting and Analysis, Section: "Monitor Account Balances". This section details the functionality of the Account Monitor for tracking account balances against targets and tolerances.

2. Oracle University, Oracle Fusion Cloud General Ledger 2023 Implementation Professional Courseware, Module: "Period Close", Topic: "Using Account Monitor for Reconciliations". The courseware explains how Account Monitor helps in proactively identifying issues during the close process.