Question $10(2\mathrm{.}5$ points$)$

In order to minimize diversifiable risk in our portfolio, we might pursue any of the following approaches except:

invest in $25$ stocks or more stocks that were not positively correlated

buy an index fund

invest in at $5-10$ stocks with less than $1\mathrm{.}0$ positive correlations

invest in an equity mutual fund that might include something like $150$ different stocks