Refer to the below equation :

Question

Which of the following is correct order of decreasing rate of elimination of with various bases

(a)$RO^-$ > $OH^-$ > $CN^-$ > $COO^-$ >$NO_3^-$

(b)$NO_3^-$ > $COO^-$ > $CN^-$ > $OH^-$ > $RO^-$

(C)$CN^-$ > $OR^-$ > $NO_3^-$ > $COO^-$ >$OH^-$

(d)$OH^-$ > $COO^-$ >$NO_3^-$ > $OR^-$ > $CN^-$