Q has to be regular

Q cannot be regular

Q need not be regular

Q cannot be a CFL

union and complementation has to be closed under intersection

intersection and complement has to be closed under union

union and intersection has to be closed under complementation

both 1) union and complementation has to be closed under intersection and 2) intersection and complement has to be closed under union

generate an inherently ambiguous language

generate an ambiguous language but not inherently so

are unambiguous

can generate all possible fixed length valid computation for carrying out addition, subtraction, multiplication and division, which can be expressed in one expression

I only

I and II

II and III

II only

equal number of a ′s and b ′s

odd number of a ′s and odd number b ′s

even number of a ′s and even number of b ′s

odd number of a ′s and even number of a ′s