Final answer:
Cash equivalents are short-term, highly liquid investments that can be easily converted into known amounts of cash.
Step-by-step explanation:
The correct answer is d. all of these.
Cash equivalents are short-term, highly liquid investments that can be easily converted into known amounts of cash. They are considered to be very close to cash and are included as part of a company's cash and cash equivalents on the balance sheet. Examples of cash equivalents include treasury bills, commercial paper, and money market funds.
These assets meet all the criteria mentioned in the options - they are purchased with excess cash, have original maturities of three months or less, and are readily convertible into known amounts of cash. Therefore, the correct option is d. all of these.