Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
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( f ) to retain a copy , you must either have a printer connected to your personal computer or other device or , alternatively , the ability to save a copy through use of printing service or software such as adobe acrobat ® . 

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. OPTIONS: ["Limitation of liability", "Contract by using", "Choice of law", "Arbitration", "None", "Jurisdiction", "Content removal", "Unilateral termination", "Unilateral change"].