Sometimes called network marketing, multi-level marketing (MLM) is a form of sales whereby products are sold directly to customers using relationship referrals. In this hierarchical sales model, sales people receive a commission not only on their own sales, but also on the sales of those distributors they have recruited to the business. Multi-level marketing operations claim to be an easy way to generate a large income by selling products to family and friends. Does it sound too good to be true? It probably is. MLMs are the subject of controversy and numerous lawsuits: critics view them as pyramid schemes, which are illegal in most countries. A business dependant on its sales force continually finding more and more new recruits is inherently unsustainable. Even if the product is of a high quality, at some point the market will become saturated. Although a few distributors high up in the chain can earn large amounts, distributors further down in the hierarchy will rarely profit  losing much of their commission to their superiors. Furthermore, distributors are often required to invest heavily in stock and pay for expensive training courses or motivational materials. While MLMs are not illegal and not all network marketing organisations rely on the recruitment of distributors, any business designed to sell an opportunity rather than a product is both economicallyflawed and ethically questionable.

Question: MLMs are a legal but morally dubious form of pyramid scheme.
Options:
A. true, B. false, C. uncertain
Answer: "C"