Why is investment in the real economy discouraged in South Africa according to the passage?

A、 Because the economy in South Africa is heavily dependent on short-term speculative investment.
B、 Because South Africa has put too much investment in import and does not have enough money.
C、 Because South Africa has not earned profit from export to invest in the real economy.
D、 Because the situation in South Africa is unstable and thus its economy is unsustainable.