vikaschanumolu
Before they will consider a settlement, the striking teachers demand that the school board fire the substitute teachers
and establishes payment scales guaranteeing cost of living increases.(B) and to establish payment scales that would guarantee cost of living increases
Subjunctive verb 'demand' requires base form of the verb
such as (a)
I request that he write to her (instead of he writes to her) (b)
She asked that they be told immediately (instead of they were told)
Similarly in the above sentence we have "
the striking teachers demand that the school board fire the substitute" (Instead of fires). We have a conjunction here 'AND' which means we need to maintain parallelism. Here in this sentence, 'fire' and 'establishes' must be parallel ( Verb base form 'Fire' is parallel to 'Establish').
For Option B - We have 'and to establish', '
to establish' is not parallel to 'fire' (
'to' distorts the parallelism). The term 'establish' is parallel to 'fire'.
Only option D satisfies the above. Hence, DHope this helps