$*)\begin{cases}C_{15}H_{31}COOH:x mol \\ C_{17}H_{35}COOH:y mol\\C_{17}H_{31}COOH:z mol \end{cases}\Rightarrow \begin{cases}x+y+z =0,05 mol\\ 16x+18y+18z=\frac{19,04}{22,4} mol\\16x+18y+16z=\frac{14,76}{18} \end{cases}$$\Rightarrow \begin{cases}x=0,025 mol \\ y=0,01 mol\\z=0,015 mol \end{cases}\Rightarrow \%n_{linoleic}=\frac{0,015.100}{0,025+0,01+0,015}=30\%$
$\Rightarrow Chon:B$