Answer
It is not possible, see explanations.
Work Step by Step
Step 1. Assume the amount of type-A is $x$ (oz.), the amount of type-B is $y$ (oz.), and the amount of type-C is $z$ (oz.).
Step 2. Given the total amount of niacin (9mg), thiamin (14mg), and riboflavin (32mg) each, we can setup the following equations: $2x+3y+z=9, 3x+y+3z=14, 8x+5y+7z=32$
Step 3. From the first equation, we get $z=9-2x-3y$, back-substitute to the other two equations, we have
$3x+y+3(9-2x-3y)=14$ and $8x+5y+7(9-2x-3y)=32$
Step 4. Simplify the above two equations, we get $3x+8y=13$ and $6x+16y=31$, now multiply the first equation by two to get $6x+16y=26$ compare this with the second equation we get $6x+16y=26=31$ which mean that there are no solutions to the equations.
Step 5. We conclude that it is not possible to satisfy the experimental requirements.
