H2N−NH2,KOH/ethyleneglyco
Zn−Hg/HCl
Ni/H2
NaBH4
Correct option is A. Zn−Hg/HCl. Both Wolff-Kishner and Clemmensen reduction are used. The latter is not suitable as it will also attack the -OH group of the ring. Therefore, A is the correct option.