When graphing the risk-return of a two security protfolio, with expected returns on the y-axis and standard deviations on the x-axis, which of the following is not true?

a)there will be a curve when the correlation coefficient between the returns on the securities is 1.

b)a)there will be a curve when the correlation coefficient between the returns on the securities is 0

a)there will be a curve when the correlation coefficient between the returns on the securities is -1

d)all of the listed are true