The overall complex dissociation equilibrium constant for the complex $[Cu(NH_3)_4]^{2+}$ ion will be (given $\beta_4$ for this complex is $2.1 \times 10^{13}$,where $\beta_4$ is the association constant).

• A
  $4.7 \times 10^{-14}$
• B
  $2.1 \times 10^{13}$
• C
  $11.9 \times 10^{-2}$
• D
  $2.1 \times 10^{-13}$