The Average Rate of Disappearance of I^- between 400 S

The average rate of disappearance of I^- between 400 s and 800 s is M/s.

A) 1.4 × 10^{- 5}
B) 3.6 × 10⁴
C) 5.8 × 10^{- 5}
D) 2.6 × 10^{- 4}
E) 2.8 × 10^{- 5}