Until recently, many developing countries:. a. sealed themselves off from foreign investment.
b. were quite open to foreign investment.
c. encouraged foreign portfolio investment but discouraged foreign direct investment.
d. encouraged foreign direct investment but discouraged foreign portfolio investment.

a. sealed themselves off from foreign investment.

Explanation:

Traditionally it was believed that foreign direct investment means giving up the country's sovereignty to the foreign nation, on the other hand, the current people see it as a gift to the economy of a country. It becomes a known fact today that the world's economy so closely intertwined, that developing countries have no choice but to accept foreign direct investment. Opening up the domestic markets results in benefits for several nations because they might not have the resources to start profitable operations in these sectors.

answer; trojan horse;