Foreshadowing is clues or hints given by the author about future events.
A motif is essentially a theme (in literature).
Irony as a literary technique is used to express the opposite of the literal meaning of something (usually used humorously).
Flashbacks are basically the opposite of foreshadowing - they interrupt the chronological order of a story and usually provide context for events, or a backstory.
Answer:
B. Foreshadowing