The type(s) of merger(s) that directly increase(s) concentration in an industry is (are)

Which of the following is false?

a. Once a country has a comparative advantage in producing a good, that comparative advantage will always continue. b. If you can mow the lawn at home faster than your younger brother, you have a comparative advantage over him in mowing the lawn. c. Restrictions on trade will reduce people's degree of specialization according to comparative advantage d. As practice at producing what you have a comparative advantage in makes you better at it, your comparative advantage would tend to increase.

How does the value of land change when interest rates increase?