The correct option is B B2H6
B2H6 is a highly reactive and versatile reagent. It react violently with water to form hydrogen and boric acid.
B2H6+6H2O→2B(OH)3+6H2↑; ΔH=−466 kJ/mol
CH4 does not react with liquid water but it will react with gaseous water to form carbon dioxide, carbon monoxide and hydrogen. This reaction is endothermic so it needs heat energy for the reaction to take place.
H2S doesnt react with water, it just dissociate as HS−,S2−and H+ in water.
PH3 is non polar compound so it doesn't dissolve in water so there is no reaction between them.
Hence, Diborane react easily with water to produce hydrogen.