How Were Cathinones, Derived from the Khat Plant, First Introduced

How were cathinones, derived from the khat plant, first introduced to the Western world?

A) In 1887, German missionaries in Ethiopia discovered that the khat plant was ideal for increasing blood pressure.
B) In 1944, Leandro Panizzon, a chemist working for the Ciba Pharmaceutical Company, discovered the khat plant while vacationing in east Africa.
C) In the mid-1500s, Spanish conquistadors first discovered the khat plant during their conquest of the Incan empire in Peru.
D) Peter Forsskal, a Dane, discovered the khat plant during an expedition to Arabia in 1760.