Answer: Liability account
Explanation:
This is a case of looking it from bank's point of view or from the books of the bank.
Customer has deposited their money in the bank. For a certain fee. The money is secured by the bank and can be withdrawn by the customer anytime they want to. Hence cash is increased but it is still a liability for the bank since they do not have a claim to that money. It's the customers assets they are securing.