  We study a ring geometry, coupled to two normal metallic leads, which has a
Majorana bound state (MBS) embedded in one of its arm and is threaded by
Aharonov Bohm ($\mathcal{A}\mathcal{B}$) flux $\phi$. We show that by varying
the $\mathcal{AB}$ flux, the two leads go through resonance in an
anti-correlated fashion while the resonance conductance is quantized to $2
e^2/h$. We further show that such anti-correlation is completely absent when
the MBS is replaced by an Andreev bound state (ABS). Hence this
anti-correlation in conductance when studied as a function of $\phi$ provides a
unique signature of the MBS which cannot be faked by an ABS. We contrast the
phase sensitivity of the MBS and ABS in terms of tunneling conductances. We
argue that the relative phase between the tunneling amplitude of the electrons
and holes from either lead to the level (MBS or ABS), which is constrained to
$0,\pi$ for the MBS and unconstrained for the ABS, is responsible for this
interesting contrast in the $\mathcal{AB}$ effect between the MBS and ABS.
