The answer is B. It made Manifest Destiny a law.
Affect - someone causing something.
Effect - the result of what was caused.
EX: Destroying trees negatively affects the wildlife.
EX: The effect that destroying trees has on wildlife is negative.
Answer: B. In school, my mother encouraged me to join the band.
The modifier in this case is misplaced as it makes it sound like the mother was at school when she gave the advice. Modifiers can be very important to the structure of a sentence as they can significantly change the meaning if misplaced.
All the other examples express the meaning of the sentence clearly.
Prepositional Phrase I’m working on the same thing and have a list of those phrases