[Elton's Electronics] Elton's Electronics Sells Electronic Housewares

[Elton's Electronics] Elton's Electronics sells electronic housewares. Elton is looking for a new supplier to produce the standard-sized switchplate for its best-selling blender. He contacts Porter and provides Porter with specifications for where the switches on the switchplate should be placed. Porter provides excellent pricing and delivery terms, which would save Elton a lot of money. Elton and Porter sign a contract for Porter to produce 10,000 standard-sized switchplates according to Elton's specifications. When the completed switchplates arrive, Elton's employees attach them to the blenders, however, the standard-sized switchplates are two millimeters too long. Elton is furious and calls Porter, who says Elton can send back the switchplates and Porter's company can rework them, but there will be a fee because the switchplates he shipped were "standard-size" switchplates, as specified in the contract. Elton disagrees and hangs up the phone. Elton's technician measures both the switchplates and the blender and discovers that the blender face where the switchplate is attached is two millimeters shorter than the well-known "standard-size" switchplate. The technician suggests they could shave off two millimeters from Porter's boards to make them fit on the blenders, however, it would be a lot of work.
-Which of the following best describes Elton's situation?

A) Fraudulent misrepresentation, because Elton justifiably relied on a false statement by Porter.
B) Mutual mistake, because both parties were mistaken about the standard-size switchplates to be delivered under the contract.
C) Unilateral mistake, because Elton was mistaken about the size of the switchplates he needed for his blenders.
D) Duress, because Porter knows much more about the standard size for switchplates in the industry than Elton.
E) Negligent misrepresentation, because Porter should have known that the standard-size may not work for everyone.