1. The Contracting parties may establish such stipulations, clauses, terms and conditions as they may deem convenient, provided they are not contrary to law, morals, good customs, public order, or public policy. a. Autonomy of contracts b. Mutuality of contracts. c. Relativity of contracts d. Consensuality of contracts. 2. The contracts must bind both contracting parties, its validity or compliance cannot be left to the will of one of them. a. Autonomy of contracts. b. Mutuality of contracts. c. Relativity of contracts d. Consensuality of contracts 3. Contracts take effect only between the parties, their assigns and heirs. a. Autonomy of contracts b. Mutuality of contracts c. Relativity of contracts. d. Consensuality of contracts 4. Contracts are perfected by mere consent and from that moment the parties are bound not only to the fulfillment of what has been expressly stipulated but also to all the consequences which, according to their nature, may be in keeping with good faith, usage and law. a. Autonomy of contracts b. Mutuality of contracts. c. Relativity of contracts d. Consensuality of contracts. 5. The following are the essential requisites of contracts, except: a Consent of the contracting parties. b. Object certain which is the subject matter of the contract c. Cause of the obligation which is established, d Qualified offer of one of the parties which constitutes a counter-offer. 6. The following are requisites for a cause to be valid, except. a. It must be qualified by one of the parties b. It must exist at the time of the contract is entered into. c. It must be lawful. d. It must be true or real 7. The following are special forms of payment, except: a. Dacion solvendi b. Dation in payment. c. Payment in cession d. Tender of mavment and consisnation