The production of leather and fur for clothing is labor intensive, which means that these materials have tended to be expensive.
Situation
Producing leather and fur is labor intensive, so these materials will tend to be rather expensive.
Pivot (But) As fashion has moved away from these materials, their prices have dropped.
Meanwhile, as other products (less labor-intensive to produce) have become more fashionable, the price of these materials has risen.
Evaluate
When we're doing one of these Proposition / Generalization type question stems, the correct answer is usually a safely worded takeaway that reinforces the Causal Difference-Maker.
We have causal language in the first sentence: which means that
So we know that "how labor intensive something is" can affect its price.
But the covariation we have in the final sentence also suggests a Causal Difference-Maker: as leather/fur got less fashionable, the price dropped. as other materials got more fashionable, their price rose.
Goal
We probably are going to hear something like (aloofly referring to fashion status as another causal factor).
Trap answers on this type of question are often Too Strong, so look out for stuff like .