  We develop a systematic method to classify connected \'etale algebras $A$'s
in (possibly degenerate) pre-modular category $\mathcal B$. In particular, we
find the category of $A$-modules, $\mathcal B_A$, have ranks bounded from above
by $\lfloor\text{FPdim}(\mathcal B)\rfloor$. For demonstration, we classify
connected \'etale algebras in some $\mathcal B$'s, which appear in physics.
Physically, the results constrain (or fix) ground state degeneracies of
(certain) $\mathcal B$-symmetric gapped phases. We study massive deformations
of rational conformal field theories such as minimal models and
Wess-Zumino-Witten models. In most of our examples, the classification suggests
the symmetries $\mathcal B$'s are spontaneously broken.
