Justify your answer. Use civil code to support claims.

Q19 A is the owner of a cow. He sold the same to B. B paid for the cow. A found another person, C, who was interested in the cow and who was willing to pay more than what B paid him. A sold and delivered the cow to C. (A) Did A do the right thing? (B) What could be the course of action of B? (C) What is C's right over the cow?

Q20 (A) How do you differentiate an obligation with a retroactive effect from an obligation with a prospective effect? (B) Give an example of each.