A mass $1 \mathrm{~kg}$ suspended from a spring whose force constant is $400 \mathrm{Nm}^{-1}$, executes simple harmonic oscillation. When the total energy of the oscillator is $2 \mathrm{~J}$, the maximum acceleration experienced by the mass will be
(a) $2 \mathrm{~ms}^{-2}$
(b) $4 \mathrm{~ms}^{-2}$
(c) $40 \mathrm{~ms}^{-2}$
(d) $400 \mathrm{~ms}^{-2}$