Which of the following statements are correct ?

Question

(i) $RO^{-} $ is a stronger nucleophile than $OH^{-}$
(ii) $RCO_2^-$ is a stronger nucleophile than $OH^-$
(iii) $RCO_2^-$ is a stronger nucleophile than $ROH$
(iv) $RO^{-}$ is a weaker nucleophile than $OH^{-}$

$ (a)\;(i)\; and\;(iii) \\ (b) \; (ii)\;and \;(iii) \\ (c) \;(i)\;and \;(iv) \\ (d)\;(ii)\;and (iv) $