question: storage:optical disk:hard disk
choices.label: A B C D
choices.text: drying:rope:hanger eat:steel fork:spatula writing:signature pen:writing brush swimming:swimming ring:swimming suit
explanation: both "optical disk" and "hard disk" belong to computer parts, and the main functions of "optical disk" and "hard disk" are used for "storage". the main function of a "rope" is to bind and connect, not "dry", the main function of a "hanger" is to "dry". the main function of a "spatula" is to cook, not to "eat". both the "signature pen" and the "writing brush" belong to the category of tools, and the main function of the "signature pen" and "writing brush" is to "write". the main purpose of the "swimming ring" is to ensure the safety of "swimming", and the "swimming suit" should be worn when "swimming". "swimming" is not a function of the "swimming suit".
relation: optical disk hard disk R2.4
relation: signature pen writing brush R2.4