
    In a bank's fraud detection system, given a list of transaction pairs where each pair contains a transaction ID and its associated risk score, identify the transaction ID of the most suspicious activity (transaction with the lowest risk score) for immediate investigation. The system processes transaction pairs in the format (transaction_id, risk_score), where lower risk scores indicate potentially fraudulent activities.
    

    
from operator import itemgetter

def index_minimum(test_list):
    """
    In a bank's fraud detection system, given a list of transaction pairs where each pair contains a transaction ID and its associated risk score, identify the transaction ID of the most suspicious activity (transaction with the lowest risk score) for immediate investigation. The system processes transaction pairs in the format (transaction_id, risk_score), where lower risk scores indicate potentially fraudulent activities.
    

    """
from operator import itemgetter

def index_minimum(test_list):
    """
    In a bank's fraud detection system, given a list of transaction pairs where each pair contains a transaction ID and its associated risk score, identify the transaction ID of the most suspicious activity (transaction with the lowest risk score) for immediate investigation. The system processes transaction pairs in the format (transaction_id, risk_score), where lower risk scores indicate potentially fraudulent activities.
    

    """
    res = min(test_list, key=itemgetter(1))[0]
    return res