The main reason that france signed a formal alliance with the colonies during the american revolution was:
the formation of the continental congress.
great britain’s victory at the battle of saratoga.
the colonial victory at the battle of saratoga.
benjamin franklin’s negotiations on their behalf.

I believe the answer is: the colonial victory at the Battle of Saratoga.

At that time, the french empire was on the fence in whether they need to provide help for the colonist or not. After the victory at the battle of saratoga, The french government saw a potential in the revolutionary army and decided to formed a formal alliance to aid them.

when studying cause and effect, historians usually group the causes into different categories. for example, cultural causes reflect how a society’s literature and art convey the way the society saw itself in relation to the rest of the world. another resource that historians use to understand society is pop culture, which tells them the trends and ideas that are preferred by the common people. when studying cause and effect, it’s important to remember multiple causation, or the idea that an effect could have several causes and vice versa.  

the correct option is “cultural causes” since art and literature are related to the culture of a place. culture is determined by literature, art, music.

the correct option is “pop culture” since it reflects the likes and ideas of common people whereas the rest of the options do not focus on common people.  

the correct option is “multiple causation” since it refers to the idea that events are caused by multiple reasons, not just a single one.