One of the advantages of the mean$-$variance framework is that:

select one

$$ A$.$ a$.$ Optimized portfolios are insensitive to small changes in the inputs.

$$ B$.$ b$.$ The risk and return characteristics of a portfolio are easily determined from the corresponding characteristics of the individual assets.

$$ C$.$ c$.$ Optimized portfolios rarely contain "corner solutions" with zero$-$weights on some of the assets.

$$ D$.$ d$.$ The risk and return characteristics of portfolios are well$-$described even if those of the individual assets are