Only valid options are B and D, because of parallelism single out, begin trade and
....conclude + conclude by
- is ok in the following sentence (negotiations were concluded by
his secretary of state), but here we have different meaning in our sentence. conclude with
- is ok, ( the talk concluded with slides ) but it requires noun with US goverment's satisfaction will be ok. But not being ...., + parallelism problemconclude to
- is also ok, because TO concerns to US satisfaction. Satisfaction, satisfaction (nice track))))
D. Hope it's useful
The greatest pleasure in life is doing what people say you cannot do...