The correct answer is (3) the use of poisonous gas and submarine attacks
Answer: New threat or perceived opportunity
Explanation:
According to sociologist doug mcadam, a new threat or perceived opportunity must occur for a social movement to arise. It's been realized by him that what will spur or arise the intentions of a group of people to achieve a goal that was either forgotten, dead or a new one is by a new threat or a perceived opportunity. In most cases threat tends to spur individuals to take situations serious and would want an outcome.