Answer:
A. Money Market checking account
Step-by-step explanation:
A money market account represents a savings account with some features of a checking account provided by a bank. Herein, a customer deposits money, and such funds are invested into money market instruments which are highly liquid, such as commercial papers, treasury bills, certificate of deposits, etc.
Such accounts provide debit card and checks and allow a certain number of withdrawals every month. The rate of interest offered under these accounts is usually higher than the ordinary savings account.
In the given case, the customer has $20,000 to invest and also requires immediate access to the funds to pay his bills. The best recommendation would be to deposit such funds to a money market checking account, which would provide him with access i.e liquidity, a higher rate of interest than on savings account and safety of investment.
It is noteworthy that all other options specified are not as liquid as money market checking account since, those alternatives either require considerable time in redeeming and selling or do not provide immediate access to funds.