We have to calculate the unit price for each option, this is price/amount, so:
[tex]\begin{gathered} A-\frac{3.2}{16}=0.2 \\ B-\frac{5}{32}=0.15625 \\ C-\frac{2.5}{10}=0.25 \\ D-\frac{4.5}{8}=0.5625 \end{gathered}[/tex]The lowest unit price is option B $0.15625/oz.
