The correct answer is: tighten and contract
This is is the correct
answer because muscle fibers need to first reach an optimal length and
tension ratio or "tighten" in order for the muscle to perform work.
After the muscle has tightened, it can then "contract" which leads to a
decrease in the angle of the joint through force. If the muscle being
used to pull the rope is the bicep on the arm, then the angle between
the forearm and upper arm will decrease, causing the rope to be pulled.
