Option E encompasses several red flags that collectively suggest suspicious activity: refusal to provide ID, secretiveness, refusal to meet in person, and cash payments. These behaviours indicate potential money laundering or other illicit activities. Therefore, Emily should report her suspicions to the firm's MLRO. Options A through D describe situations that could occur in routine legitimate matters and, in isolation, do not necessarily indicate money laundering. Delays in providing ID, requests for work outside the usual scope, early termination of transactions, and payments to third parties can all have legitimate explanations. 

Key Point: This question tests the ability to identify suspicious behaviours that may indicate money laundering. Solicitors must be vigilant and understand when to escalate concerns to their MLRO to ensure compliance with anti-money laundering regulations.