Explain whether each of the following transactions results in a valid negotiation, be specific, refer to the law of business for each:

a. Arnold gives a negotiable check payable to bearer to Betsy without indorsing it.

b. Golden indorses a negotiable promissory note payable to the order of Golden, "Pay to Chambers and Rambis, (signed) Golden."

c. Porter lost a negotiable check payable to his order. Kersey found it and indorsed the back of the check as follows: "pay to Drexler, (signed) Kersey."

d. Thomas indorsed a negotiable promissory note payable to the order of Thomas, "(signed) Thomas," and delivered it to Sally. Sally then wrote above Thomas's signature "Pay to Sally."

e. Margarita issued to Poncho a negotiable promissory note payable to the order of Poncho. Poncho indorsed the note "Pay to Randy only, (signed) Poncho" and sold it to Randy. Randy then sold the note to Stephanie after indorsing it "Pay to Stephanie, (signed) Randy."