Final answer:
New Brunswick's main motivators for joining Confederation were economic stability and defense concerns, which align with the broader economic and security challenges of the time.
Step-by-step explanation:
New Brunswick's Motivators for Confederation
The two main motivators for New Brunswick to join the Confederation were economic stability and defense concerns. This choice matches option A. The desire for economic stability was significant, especially after experiencing economic growth under mercantilist policies, which saw the colonies engage in a beneficial trade network with the British empire. In addition to economic reasons, defense concerns also played a vital role as the colonies needed to ensure their protection against potential threats and maintain order within their growing territories.