  The event GW170817/GRB 170817A, discovered via the successful joint
observation of its gravitational wave radiation and its multi-wavelength
electromagnetic counterparts, was the first definite "smoking-gun" from the
merger of two neutron stars (NSs). However, the remnant of the merger remains
unknown. Piro et al. recently claimed that a low-significance X-ray variability
in GRB 170817A. By systematically comparing the properties of variability in
the afterglow of GRB 170817A and X-ray flares in GRB afterglows, we find that
this X-ray variability seems to share similar statistical correlations with
X-ray flares in GRB afterglows. We further investigate several possible merger
product scenarios to see whether they can produce the observed X-ray
variability in GRB 170817A. The first scenario invokes a stable magnetar as the
central engine producing the later X-ray variability via differential rotation
or fall-back accretion onto the NS. The second scenario invokes a black hole as
the central engine with a fall-back accretion process. The final scenario is a
central engine with a long-lived supra-massive NS. We find that the first two
scenarios have difficulty producing the later X-ray variability, which requires
either an impractical NS magnetic field or an extraordinarily large stellar
envelope and an extremely long accretion timescale. However, the third scenario
seems to be consistent with observations, and the later X-ray variability can
be produced by the magnetosphere which is expelled following the collapse of
the NS with a $B_p\in(3.6, 13.5)\times10^{13}$ G.
