Consider the following statements regarding full-reserve banking and fractional-reserve banking:

1. In full-reserve banking, banks are required to hold all the money they receive from customers as demand deposits in their vaults at all times.

2. In full-reserve banking, banks can only lend money that they have received as time deposits.

3. In fractional-reserve banking, banks primarily lend electronic money and can create loans exceeding the actual physical cash they hold.

4. Full-reserve banking allows banks to freely influence the economy's money supply, leading to possible economic booms and busts.

How many of the above statement(s) is/are correct?