Answer: C. main idea and theme
Explanation: The main idea of a text refers to its overall message or central point. In this case, the main idea is about a group of teenagers saving the earth from giant spiders. This summarizes the general plot of the movie.
On the other hand, the theme is the underlying message or lesson that the movie conveys. In this case, the theme is that anyone can be a hero with the help of their friends. This theme highlights the importance of teamwork and the potential for ordinary individuals to rise to heroic actions.