The element ytterbium increases its electrical resistance when subject to high mechanical stresses. This property has made it an indispensable component in a medical tool designed to measure the stress on bones, which can guide physicians in setting broken bones. Unfortunately, ytterbium is rare, found in only a few meager sources around the world. A steep market demand will cause the price to skyrocket, and this technology so helpful to physicians will become unaffordable.Which of the following, if true, most seriously weakens the argument above?
【选项】The process of extracting pure ytterbium from its ores, euxenite and xenotime, is very expensive and involves strong acids.