Question 23M.1.HL.TZ1.19

Which calculation determines the initial rate of this reaction?

A.  $\frac{0.40-0.19}{20-0}$

B.  $\frac{0.40-0.10}{40-0}$

C.  $\frac{0.40-0}{140-0}$

D.  $\frac{0.40-0.20}{10-0}$