The sentence "Fustian writing is where you write pompous, bombastic nonsense." is illogical for the following reasons:
1. Fustian, like the sentence implies, means pretentious speech or writing.
2. Fustian writing does not refer to a place.
3. The word <em>where </em>is used to refer to a place.
4. Using the word <em>where </em>implies that<em> fustian writing</em> is a place, which is wrong.
Therefore, one can correct the sentence and say this instead: Fustian writing is when you write pompous, bombastic nonsense.
A direct object is the part of the sentence that is somehow manipulated by the subject, and the type of the manipulation is described by the verb.
here the subject is "The delighted children" and the verb is "picked"
the direct object is "pumkins" - the correct answer is d.
It's got to be C because none of the others relate to collaboration, but I'd say if you were unsure about this answer then the only other sensible one could be B, but I'd go with C.