What kind of defective contracts are the following? Why?

11. A contract of barter or exchange of a human heart for a human liver.*

12. A contract whereby the City of Baguio donated Bakakeng Road to SLU.

13. A contract whereby A will kill B's mother-in-law in exchange for two-piece Jollibee Chicken Joy with fries.

14. A contract between a 16 years old and a 17 years old.

15. A contract between a 16 years old and an insane or demented person.

16. A contract between a 17 years old and a deaf-mute who does not know how to write.

17. A contract whereby A, without authority, borrowed money for and in the name of B.

18. A gave B the authority to lease his house and lot to C. But B instead sold the house and lot to C. The sale is:

19. An oral contract that by its terms is not to be performed within a year from its making.

20. An oral promise to pay answer for the debt of another.

Choices:

A. Rescissible

B. Voidable

C. Unenforceable

D. Void or Inexistent