[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.
-Under which of the following scenarios would a court most likely invalidate the contract with Porter?

A) If Porter knew the "standard-size" switchplates were not the proper size for Elton's blenders, and Elton's mistake in calculating the size needed was a clerical error.
B) If Elton's technician "eyeballed" the size needed for the blender.
C) If Elton wrote the wrong switchplate size in an email to Porter and that size was the same as the standard size.
D) If Elton's mistake in measuring the size of the switchplate needed was a clerical error.
E) If Elton assumed the switchplate was the standard size.