Please help with the following questions. Thank you!

Problem 6. (1 point) Suppose that C = f(x.r) = 26:6{5'3' represents the concentra tion (in mg/liter) of a drug in the blood 1* 2 0 hours after .1: mg of the drug is injected. (a) Evaluate f0. 3) = (b) Give a practical interpretation of your answer in part (a): f{2.3) is... o A. the amount of a 3 mg dose in the blood 2 hours after injection. 0 B. the change in concentration of a 2 mg dose in the blood 3 hours after injection. 0 C. the concentration of a 2 mg dose in the blood 3 hours after injection. Problem 7. (1 point) Find the indicated partial derivatives of: _ 3x 8}! fix:}') _ 3x _ 9'}!- Problem 8. (1 point) Find the indicated partial derivatives of: fix: y) : Ivy-'94&quot