Aresearcher wants to examine whether there is a difference in stress levels between single and married mothers of young children. what would an appropriate null hypothesis be for this study?

In a research study which sets out to examine whether there is a difference in stress levels between single and married mothers of young children, an appropriate null hypothesis for the study would be: “There is no difference in stress levels between single and married mothers of young children”

i think its toxic gasses but i could be wrong