Your eccentric Aunt Claudia has left you $50,000$ in BP shares plus$50,000$ cash. Unfortunately, her will requires that the BP stock not be sold for one year and the $50,000$ cash must be entirely invested in one of the stocks shown below. $[[,$BHP$,$Billiton,BP$,$siemens,Nestl$,$Sony,Sanofi,$[[$Agricultural$],[$Bank$]]],[$BHP Billiton,,$1\mathrm{.}00,0\mathrm{.}44,0\mathrm{.}21,-0\mathrm{.}05,0\mathrm{.}21,0\mathrm{.}15,0\mathrm{.}24],[$BP$,,,1\mathrm{.}00,0\mathrm{.}40,0\mathrm{.}24,0\mathrm{.}27,0\mathrm{.}36,0\mathrm{.}27],[$Siemens$,,,,1\mathrm{.}00,0\mathrm{.}26,0\mathrm{.}33,0\mathrm{.}29,0\mathrm{.}21],[$Nestl$,,,,,1\mathrm{.}00,0\mathrm{.}34,0\mathrm{.}27,-0\mathrm{.}06],[$Sony$,,,,,,1\mathrm{.}00,0\mathrm{.}27,0\mathrm{.}35],[$Sanofi$,,,,,,,1\mathrm{.}00,0\mathrm{.}17],[$Agricultural Bank,,,,,,,,$1\mathrm{.}00],[$Standard deviation, $,,26\mathrm{.}2,22\mathrm{.}8,22\mathrm{.}5,13\mathrm{.}6,27\mathrm{.}6,17\mathrm{.}5,25\mathrm{.}5]]$ a$.$ Calculate the portfolio variance for seven different portfolios. Note: Use decimals, not percents, in your calculations. Do not round intermediate calculations. Enter your answers as a decimal rounded to $5$ places. b$.$ What is the safest attainable portfolio under these restrictions? Complete this question by entering your answers in the tabs below. Required A Calculate the portfolio variance for seven different portfolios. Note: Use decimals, not percents, in your calculations. Do not round intermediate calculations. Enter your answers as a decimal rounded to $5$ places.