Either add the passage with the question so we know what you are referring to or do not post questions like these. Not everybody has read what you have. This question is completely useless and unanswerable without the story to go off of.
Yes, it can, depending on the word. Prefixes, however, almost never change the root word. The most common changes of a root when adding suffixes are the removal of a final E that follows a consonant (e.g. diving), or the change of a Y to an I (e.g. silliness).
The answer is B. Marcus wants a digital camera, but he can't decide on the model.
Answer:
They journey took me _some_ hours
