Answer:
B) Valves closing
Explanation:
A healthy heart makes a lub-dub sound with each beat. This sound comes from the valves shutting on the blood inside the heart. The first sound (the lub) happens when the mitral and tricuspid valves close.
Arrector pili muscle is the one with hair follicles that has a smooth muscle which is in an unconscious control rather than conscious control. This pull up the follicle causing the goose bumps then. Hope this is the right answer and will be of big help then.
Ask this in the physics area next time please, but turn to someone you trust or if your young an adult, like your parents or your teachers. Maybe even your friends. No matter what age tell someone and if they don't know then get medical help if they can't.
Talk to someone about your feelings, do things that make you happy, have a balanced food diet