Which of the Following Characteristics Do Skeletal Muscle and Smooth

Which of the following characteristics do skeletal muscle and smooth muscle have in common?

A) Calcium is bound by the protein calmodulin prior to formation of cross-bridges.
B) Tropomyosin is removed from the myosin-binding site on actin, permitting formation of cross-bridges
C) Sliding of thick and thin filaments relative to one another depends on a rise in cytosolic calcium.
D) Sliding of thick and thin filaments relative to one another results in shortening of the sarcomeres.
E) All of these.