The time for half life period of a certain reaction. A - products is 1 hour when initial concentration of the reactant A is $2.0\; mol\; L^{-1}$, how much time does it take for its concentration to come from $0.50$ to $0.25\;mol L^{-1}$ if it is a zero order reaction ?

Question

$(a)\;4\;hr \\ (b)\;0.5\;hr \\(c)\;0.25\;hr \\(d)\;1\;hr$