  We introduce three families of classical and quantum solutions to the leading
order of string effective action on spatially homogeneous $(2+1)$-dimensional
space-times with the sources given by the contributions of dilaton,
antisymmetric gauge $B$-field, and central charge deficit term $\Lambda$. At
the quantum level, solutions of Wheeler-DeWitt equations have been enriched by
considering the quantum versions of the classical conditional symmetry
equations. Concerning the possible applications of the obtained solutions, the
semiclassical analysis of Bohm's mechanics has been performed to demonstrate
the possibility of avoiding the classical singularities at the quantum level.
