The Reaction Below Virtually Goes to Completion Because Cyanide Ion

Multiple Choice

The reaction below virtually goes to completion because cyanide ion forms very stable complexes with Ni²⁺ ion: [Ni(H₂O) ₆]²⁺(aq) + 4 CN^-(aq) → [Ni(CN) ₄]^2-(aq) + 6 H₂O(l)
At the same time,incorporation of ¹⁴C labelled cyanide ion (¹⁴CN^-) is very rapid:
[Ni(CN) ₄]^2-(aq) + 4 ¹⁴CN^-(aq) = [Ni(¹⁴CN) ₄]^2-(aq) + 4 CN^-(aq)
Which statement below is correct with regard to stability and rate of reaction?

A) Equilibrium is static.
B) Stable species can react rapidly.
C) Stable species do not react rapidly.
D) Unstable species react rapidly.