Inspection system X and inspection system Y, though based on different principles, each detect all product flaws, but they each also erroneously reject three percent of flawless products. Since false rejections are very costly, money will be saved by installing both systems, instead of either one or the other, and rejecting only products found flawed by both.
The argument above requires which of the following assumptions
A．The three percent of flawless products that system X rejects are not all the same products, piece for piece, that system Y erroneously rejects.
B．It is less costly to accept a flawed product than to reject a flawless one.
C．In their price range, systems X and Y are the least errorprone inspection systems on the market.
D．Whichever system performs the second inspection needs to inspect only products not rejected by the first system.
E．(E) Any way of detecting flaws, other than by using either system X or system Y, requires complete disassembly of the products.