"It means Emperor of Rome who stopped the persecution of Christians and in 324 made Christianity the official religion of the Roman Empire; in 330 he moved his capital from Rome to Byzantium and renamed it Constantinople"
The correct answer is: "a handbook of government statistics
".
Government statistics are collected using objective measurament techniques and published by an official source.
The other three sources are not official, and probably, not objective as well. On the first hand, the information contained in a press realease from a company or in a claim in a political commercial, is subjected to the profit-maximization interests of a private company. On the other hand, a blog entry is very likely biased by the subjective opinion of its author.
