A 54-year-old presents 4 hours after chest pain onset. ECG is nonischemic. High-sensitivity troponin at time zero is below the assay's limit of quantitation (LoQ). Which is a reasonable approach per US guidance?ADischarge without any troponin testingBUse conventional troponin onlyCAdmit all such patients for serial enzymes for 24 hoursDSerial hs-cTn testing at 0 and 3 hours is mandatory in all cases regardless of timingEIf symptoms began ≥3 hours earlier and ECG is nonischemic, a single hs-cTn below LoQ can reasonably exclude myocardial injury and allow discharge with follow-upCheck my answer