A data engineer is analyzing customer transactions and needs to determine the maximum and minimum transaction amounts for each customer. They use the following code structure: from pyspark . sql import functions as F result_df = df . ____________ ( "customer_id" ). agg ( F . max ( "transaction_amount" ). alias ( "max_transaction" ), F . min ( "transaction_amount" ). alias ( "min_transaction" ) ) Which function correctly fills in the blank to meet the specified requirement?