Determine whether each of the following statements is True or False. Carefully explain your answer.

(a) "If Country A has an absolute advantage over Country B in all goods they produce, then Country B cannot have a comparative advantage in any of the goods because its opportunity cost of producing each good will always be higher than that of country B."

(b)"When a firm's production process generates a positive externality, imposing an appropriately chosen subsidy per unit of output is going to decrease the firm's marginal cost. This will in turn cause the firm to produce at the point where the social marginal benefit of the last unit of output is equal to the social marginal cost. The resulting quantity of output will be efficient from the social point of view."

(c) "If a firm in a perfectly competitive market experiences an increase in the variable cost of production it will pass some of that increase to consumers in the form of a higher price."

(d) "Suppose a person has lost a $50 banknote in their living room and needs to search to find it. The opportunity cost of their time is constant and is equal to $10 per hour. In this case, a rational person will not search for more than 5 hours for the $50 note."