The correct answer is she forgot to record a transaction.
Comparing the entries in Lupe’s record with the entries in the bank statement, the other mistake that Lupe made was she forgot to record a transaction.
Lupe needs to pay attention to all the bank transactions she makes in order the get a good record of transactions and have no doubts about the bank movements she makes with her money. This way, when Lupe discovers a difference between her records and the Bank’s records she can check her records to see if she made a mistake. If she doesn’t, then she can go to the Bank and ask for clarification with a Bank officer.