登录之后可查看解析

C is corrent. For an instrument to be negotiable, it must be written and signed by the maker or drawer and contain an unconditional promise or order to pay a fixed amount in money. It must also be payable at a definite time or on demand. It must be payable to order or to bearer, except in the case of a check. The instrument in the question satisfies all of these requirements and is a negotiable note.
A is incorrect. The note is payable 50 days or sooner after the date. Since the instrument is dated, it is payable at a definite time.
B is incorrect. The note does contain a fixed amount of $4,000 plus ten percent annual interest. When the note is to be paid, the exact interest can be calculated.
D is incorrect. A negotiable instrument is permitted to show that it is secured by collateral such as inventory.