In an English auction, the ________ bidder wins

Which of the following is the primary source of cross-country differences in the real earnings of workers?

a. differences in natural resource endowments b. differences in output per worker c. differences in the average number of hours worked d. differences in the share of workers that are members of a labor union e. access to modern technology

Which of the following is a possible rationing device?

A) dollar price B) first-come-first-served C) brute force D) a and b E) a, b, and c