JEE Main 2020 Chemistry question

For the following Assertion and Reason, the correct option is Assertion (A) : When Cu (II) and sulphide ions are mixed, they react together extremely quickly to give a solid. Reason (R) : The equilibrium constant of \mathrm{Cu^{2+}(aq)+S^{2-}(aq)\rightleftharpoons CuS(s)} is high because the solubility product is low.

• (A)Both (A) and (R) are true and (R) is the explanation for (A)
• (B)Both (A) and (R) are false
• (C)(A) is false and (R) is true
• (D)Both (A) and (R) are true but (R) is not the explanation for (A)Correct