Task: Class Definition Understanding (ontology: Sciences/Biology)

Which of the following definitions best describes 'N-butyl-N-(4-hydroxybutyl)nitrosamine'?

A. A lignan that is tetrahydrofuran substituted at positions 2, 3 and 4 by 4-hydroxy-3-methoxyphenyl, hydroxymethyl and 4-hydroxy-3-methoxybenzyl groups respectively (the 2S,3R,4R-diastereomer).
B. A nitrosamine that has butyl and 4-hydroxybutyl substituents. In mice, it causes high-grade, invasive cancers in the urinary bladder, but not in any other tissues.
C. A primary alcohol that is isopentane substituted by a hydroxy group at position 1.
D. A primary alcohol that is hexan-1-ol which is substituted by a methyl group and a thiol group at position 3. It is the odor component of human axilla sweat and the major species at pH 7.3.

Answer: A nitrosamine that has butyl and 4-hydroxybutyl substituents. In mice, it causes high-grade, invasive cancers in the urinary bladder, but not in any other tissues.