Answer and Explanation:
The Securities Investor Protection Corporation enhance security for the registered broker and distributor customers and national securities exchanges members
In the given situation, it is mentioned that a customer has 4 accounts i.e person cash account, person margin account, cash account jointly with his wife and custodial account for two children
Now if the firm liquidates, the (Securities Investor Protection Corporation) SIPC covers all accounts but separately i.e both person accounts are count as one by adding them, the joint account as an individual and the custodial account as an individual