The confidence index of China’s entrepreneurs rose 6.3 points in the first quarter from the same period last year, reflecting optimism in the national economy.  The benchmark index tracking domestic company managers’ confidence in the economy hit 138.8 points, "the highest level in recent years," the National Bureau of Statistics said in its report yesterday.  Manufacturers of steel and cement were among those who were the most optimistic about their future, despite the government’s decision to rein in investments in the overheated sectors this year.  "The probability of ensuring profits is a major source of the entrepreneurs’ business confidence," said Pan Chunhui, a Haitong Securities’ analyst. "Booming sales in automobiles and apartments, which consume major quantities of steel and cement, pushed up the investment sentiment."  Despite government warning that the raw material providers would suffer from oversupply this year, investment in the sectors is unlikely to cool down in the near future. This is because of the continuous price hikes in the raw materials due to booming demand.