  We present low temperature transport measurements on dual-gated suspended
trilayer graphene in the quantum Hall (QH) regime. We observe QH plateaus at
filling factors {\nu}=-8, -2, 2, 6, and 10, in agreement with the
full-parameter tight binding calculations. In high magnetic fields, odd-integer
plateaus are also resolved, indicating almost complete lifting of the 12-fold
degeneracy of the lowest Landau levels (LL). Under an out-of-plane electric
field E, we observe degeneracy breaking and transitions between QH plateaus.
Interestingly, depending on its direction, E selectively breaks the LL
degeneracies in the electron-doped or hole-doped regimes. Our results
underscore the rich interaction-induced phenomena in trilayer graphene.
