
    In a bank's transaction monitoring system, given a list of transaction pairs where each pair contains a transaction ID and its corresponding fraud risk score, find the transaction ID associated with the lowest risk score. The risk scores are numerical values calculated based on various fraud detection algorithms, and a lower score indicates safer transactions.
    

    
from operator import itemgetter

def index_minimum(test_list):
    """
    In a bank's transaction monitoring system, given a list of transaction pairs where each pair contains a transaction ID and its corresponding fraud risk score, find the transaction ID associated with the lowest risk score. The risk scores are numerical values calculated based on various fraud detection algorithms, and a lower score indicates safer transactions.
    

    """
from operator import itemgetter

def index_minimum(test_list):
    """
    In a bank's transaction monitoring system, given a list of transaction pairs where each pair contains a transaction ID and its corresponding fraud risk score, find the transaction ID associated with the lowest risk score. The risk scores are numerical values calculated based on various fraud detection algorithms, and a lower score indicates safer transactions.
    

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