In a competing pathway scenario where A can form P via k1 and Q via k2, what is the observed rate of disappearance of A?

• A. -(d[A]/dt) = k1 [A], with kobs = k1
• B. -(d[A]/dt) = k2 [A], with kobs = k2
• C. -(d[A]/dt) = (k1 + k2) [A], with kobs = max(k1, k2)
• D. -(d[A]/dt) = (k1 + k2) [A], with kobs = k1 + k2

Answer: (D)