Correct increasing order for the wavelengths of absorption in the visible region by the complexes of `Co^(3+)` is:
A. (a) `[Co(H_2O)_6]^(3+), [Co(en)_3]^(3+), [Co(NH_3)_6]^(3+)`
B. (b) `[Co(H_2O)_6]^(3+), [Co(NH_3)_6]^(3+), [Co(en)_3]^(3+)`
C. (c) `[Co(NH_3)_6]^(3+), [Co(en)_3]^(3+), [Co(H_2O)_6]^(3+)`
D. (d) `[Co(en)_3]^(3+), [Co(NH_3)_6]^(3+), [Co(H_2O)_6]^(3+)`