What is menstruation? A. A system for indicating the rhythmic relationships between notes.
B. A system for indicating the pitch relationships between notes.
C. A system for indicating the relationship between notes and lyrics.
D. A system for helping monks remember chant melodies.

Based on what i know a period is a structure of two consecutive phrases, often built of similar or parallel melodic material, in which the first phrase gives the impression of asking a question which is answered by the second phrase

Explanation: so the answer is

by acting roughly or something dramatic happening in the story.