You have average returns, variances, and the covariance for two assets. You create a spreadsheet to compute, for different allocations of the two assets, portfolio returns in column A and portfolio standard deviations in column B. You create a graph, using the data in columns A and B and the graph looks like a tilted J. What would cause this? A. The portfolios are all inefficient. B. The portfolios are all efficient. C. The axis numbers need to be adjusted so the graphs origin is not (0, 0). D. The data columns need to be switched.