The nature of contracts changed in the 19th century through judicial instrumentalism and had what effect?

(a) Facilitating free-market determinations of wages and prices.
(b) Allowing factory owners to contract with masses of employees for wages, hours and working conditions if the terms were made known and the laborers agreed to them.
(c) Advancing the rule of caveat emptor in markets because if a seller unknowingly sold defective goods, the buyer’s opportunity to inspect the goods before purchase would ensure the seller’s innocence of overt deception.
(d) All of the above were effects of the changes to the nature of contracts.