Answer:
The correct answer is option A, that is, they contain large amounts of gas and dust.
Step-by-step explanation:
A galaxy, which does not exhibit a distinguished regular shape, like an elliptical or a spiral galaxy is considered as an irregular galaxy. The irregular galaxies may comprise enormous concentrations of dust and gas.
The stars have the possibility to get formed in the irregular galaxies as they seem to exhibit huge concentrations of gas and dust, which is an essential criterion for the formation of new stars to take place.