The correct options are
A By-elections
D disqualified
A by-election is held to fill a vacant electorate seat. This can happen in case of the death or resignation of a candidate, or if an elected member is disqualified under parliamentary law.
Mid-term elections are held if the Lok Sabh or the Vidhan Sabha is dissolved before it completes its five-year term.
If an election happens after the completion of the five-year term of the legislature, it is termed as general elections.