The First-Order Reaction A $\rightarrow$ B Has K = 0

The first-order reaction A $\rightarrow$ B has k = 0.210 min^-1.If [A]₀ =0.500 M, how long will it take [A] to equal 0.115 M ?

A) 1.83 min
B) 4.55 min
C) 7.00 min
D) 20.7 min
E) 31.9 min