Select from options: Continue writing the next sentence.

How to work out a shoulder knot
Do some light stretching.
Muscle knots are basically chronic muscle strains caused by repetitive movements or postures that contract muscle fibers for long periods of time. Muscles are meant to contract for short durations, then completely relax.

Available choices:
(A). Starting with a single muscle knot isn't always possible, and even doing just slight movements could cause " pruning " or stretching that one muscle. Most people are capable of stretching 1-2 warm-up stretches, though it can take hours to do them all.
(B). Experiment with your stretches to see what is useful. Some stretches are designed for cross-training, including hip or back stretches.
(C). To do the best man's shoulder twist, take a seat or sit on a stool and lean back slightly to stretch the muscles in your arms and hands. Lower yourself to the floor on a flat, supportive surface (such as a wall or bench) and keep your back flat.
(D). However, performing similar movements over and over (due to athletics, weightlifting, cleaning the house, etc. ) or sustaining certain postures while at work strains muscles fibers and causes them to remain contracted.
Answer:
(D).