The `IUPAC` name of the well known terpene camphor having the structure
is
A. `1,7,7-`Trimethylbicyclo`[2.1.2]`heptan`-2-`ene
B. `1,5,5-`Trimethylbicyclo`[2.1.1]`hexane`-2-`one
C. `1,7,7-`Trimethylbicyclo`[2.2.1.]`heptan`-2-`one
D. `6-`Oxo`-1,2,2-`Trimethylbicyclo`[2.2.1]`heptane