Let's think about this scenario. If M is a chairperson, per the rules we must select exactly 2 tenants and 3 homeowners for the committee. There are four homeowners overall - P Q R S, but the rules also tell us that M and P cannot both be selected, hence P is out. We only have three homeowners left - Q R S and they all must be selected in a scenario when M is a chairperson.
Let me know if this makes sense and if you have any further questions.
