Who can withdraw funds and close a savings account.

Yes, any of the people named as owners of the account, if it is set up this way, have the ability to get at the money.  The three people may have a contract or other agreement among themselves about the money, and the act of taking the money out of the account might trigger rights or remedies under that contract, but none of that matters to the bank:  the withdrawal was made by someone authorized to do that, and the people who lose money because of this will have to get it back from the one who took it, not the bank.

Usually, bank accounts are not set up as "or".  They are usually joint accounts.  You can then set up limitations on who may withdraw funds and even who may deposit. Also, different rules may come into play with safe deposit boxes located in a bank. 

If this is a business account, the accounting office or manager or other designated individuals may have access to the account by virtue of their positions and thus have authorization to withdraw funds.