Given the rationale, provide a reasonable question and answer. Step-by-step reasoning process: Viruses cannot reproduce by themselves. Viruses attach themselves to cells and reproduce. Viruses cannot make copies of themselves alone. They need to attach themselves to cells.
 The question and answer:
user
How can viruses make copies of themselves?
Options:
- (A) A compound that donates proton
- (B) attach themselves to cells
- (C) have sex with another virus
- (D) distances themselves from cell
- (E) attach themselves to viruses
- (F) it needs them
- (G) rapid expansion
- (H) By wind and rain
The answer is (B)
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