I think it is D
Hope my answer help?
His eldest son gains the throne
They wanted to use tariffs to protect local manufacturers and producers from foreign competition. When you increase the tariff then importing costs more and people don't buy imported goods but buy local goods because they are cheaper. This helps domestic manufacturers and producers.
No, it is false that when you officially join a political party, you are making a lifelong commitment, since you can change your party affiliation at any time. In fact, you don't have to join any party at all.