Would like the questions answered please

15. The basic form of contracts in international trade is A. oral form B. written form C. notarial deed D. unilateral form which requires actions of each of these contracts counterparties 16. Holder in due course doctrine A. requires an unbroken chain of endorsements of an negotiable instrument to be paid B. guarantees possession of anyone whose property rights are not challenged C. requires that anyone wishing to challenge anyone else possession should do it only in a court of law D. only the buyer of a product can invoke his/her warranty rights