How Did the Use of an Implied Warranty of Merchantability

How did the use of an implied warranty of merchantability solve a set of problems with the contract law approach to product liability?

A) Consumers do not need complex contracts in order to protect themselves from all possible harms that products might cause.
B) The burden of proof has shifted from producers to consumers as consumers are allowed to assume that products are safe for ordinary use.
C) It has forced businesses to issue a disclaimer of liability and offer limited warranties to limit its liability.
D) Buyers have the responsibility to look out for their own interests and protect their own safety when buying a product.