
    Write a function that identifies the transaction ID associated with the most suspicious activity by analyzing a list of transaction-risk score pairs, where lower risk scores indicate potentially fraudulent behavior. The function should return the transaction ID from the pair that has the lowest risk score, helping the bank's fraud detection system quickly flag the most concerning transaction for immediate review.
    

    
from operator import itemgetter

def index_minimum(test_list):
    """
    Write a function that identifies the transaction ID associated with the most suspicious activity by analyzing a list of transaction-risk score pairs, where lower risk scores indicate potentially fraudulent behavior. The function should return the transaction ID from the pair that has the lowest risk score, helping the bank's fraud detection system quickly flag the most concerning transaction for immediate review.
    

    """
from operator import itemgetter

def index_minimum(test_list):
    """
    Write a function that identifies the transaction ID associated with the most suspicious activity by analyzing a list of transaction-risk score pairs, where lower risk scores indicate potentially fraudulent behavior. The function should return the transaction ID from the pair that has the lowest risk score, helping the bank's fraud detection system quickly flag the most concerning transaction for immediate review.
    

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