Thalidomide was sold as "racemic mixture" to pregnant women to treat morning sickness during pregnancy but the drug was found to harm fetus in the womb. It was banned in 1962. Which of the following reasons is the best explanation of the harmful effects of the drug?

A) Racemic mixture of any compound is always toxic and should be avoided.
B) (+)(R)-thalidomide is a sedative, but (-)(S)-thalidomide is a teratogen (a drug that is toxic in nature).
C) Thalidomide is not isomeric in nature thus causes adverse events.
D) Thalidomide was under dosed.