All of the statements about the bands observed by electron microscopy of myofibrils are true EXCEPT:

A) I bands show a hexagonal array of thick filaments.
B) thin filaments are composed mainly of actin, troponin, and tropomyosin.
C) H zones contain an array of thick filaments that are composed mainly of myosin.
D) thick filaments are joined by cross-bridges.
E) Z lines lie in the middle of the I bands, marking the ends of the sarcomere.