Answer: C. Martha's lawsuit was useful to punish the corporation for failing to pay its taxes over an eight year period.
Explanation:
In this sentence we can recognize infinitive direct-object phrase - to pay.
They can be found if we can ask a question ''what'' and in this case we are asking ''Martha's lawsuit was useful to punish what'' and then we are getting the answer which is ''to punish corporation for...'' In those kind of sentences when we are looking for the object of the verb, we must try to recognize if the infinitive phrase that we have(to punish in this case, and to pay) is making sense.
