The figure given below shows the structure of a bacteriophage. Identify its parts labelled as A, B, C and D. 

The given diagram is of bacteriophage (viruses that infect the bacteria). They have tadpole-like structure, i.e., with head and tail. Nucleic acid generally DNA is present inside the head. Tail is having hollow core end is surrounded by tail sheath. At the end of tail, end plate is present to which tail fibres are attached.