Which of the following statements is true of the monetary aspect of a promise or order in a negotiable instrument?

Multiple Choice

• The promise or order in a negotiable instrument must be to pay a fixed amount of money.
• The requirement of a "fixed amount" in a negotiable instrument applies only to interest and not principal.
• The amount of any interest payable is not described in the instrument.
• The amount of principal is calculated by reference to the formula or index referenced in the instrument if a variable rate of interest is prescribed.