Which term refers to an object that is critical to the characters in a film, but may be insignificant to the viewing audience?

A MacGuffin

Explanation:

The term MacGuffin refers to something, an episode, or character in a movie or story that helps maintain the plot in movement but has no significant importance. Alfred Hitchcock was responsible for introducing the term after borrowing it from an old story, in which he realized that the mysterious element of that story was irrelevant but still got the audience's attention and created suspense. In this way, the audience will still follow the story just to know how the mystery is revealed, even if the result is not significant.

b. the colonies must seek protection from other nations.