Which of the following is not correct regarding beta?

		If a stock has returns that are negatively correlated with market returns, then the stock has a negative beta.
		The beta of a broad market index equals one.
		If the stock's returns are uncorrelated with market returns, the beta of the stock must be zero.
		If a stock's returns are perfectly correlated with market returns, the beta of the stock must be one.

*Please explain reasoning*