The Reaction a (Aq)→ B (Aq)is First Order in [A]

The reaction A (aq) → B (aq) is first order in [A]. A solution is prepared with [A] = 1.22 M. The following data are obtained as the reaction proceeds: The rate constant for this reaction is __________ s^-1.

A) 0.23
B) 1.0
C) 0.17
D) 0.12
E) -0.12