[单选题]
The diagram below repj3xzqk(sb0l 4f l56 bbrese4(;aubs h ds *+hf6gtoy(zwrv5qk3, ints a sarcomere. Which structures are labeled I and II ?
h vdak (s* ,oyh4b5;+q 6tufrgw(zi3s
A. I is Tropomyosin ;II is Actin
B. I is Myosin;II is Troponin
C. I is Actin;II is Myosin
D. I is Myosin;II is Actin