Answer:
A- Robert <u>polished</u> his saddle.
Explanation:
If you take out "his saddle", the sentence does not make sense. Taking out "for the wagon", the sentence will still make sense. If you can take out the word(s) that the verb is applying to (what is Robert doing, he's polishing his saddle), and if the sentence does not make sense, then it is a transitive verb.
The answer would definitely have to be pestilent, as it means "destructive to life; deadly" and death would be very morbid or sad.
