In order to construct a portfolio to diversify risks as effectively as possible, what of the following characteristics among assets is the least favorable?

A The assets' returns in the portfolio tend to move oppositely

B. The covariance between each two assets' returns is above zero

C. The assets' return movements in the portfolio have no obvious tendency

D. The assets' returns are negatively correlated

In order to construct a portfolio to diversify risks as effectively as possible, what of the following characteristics among assets is the least favorable? The assets' returns in the portfolio tend to move oppositely 3. The covariance between each two assets' returns is above zero c. The assets' return movements in the portfolio have no obvious tendency D. The assets' returns are negatively correlated