Conformer of cyclohexane that are free of angle strain :--
Chair conformer is achiral as it possesses a centre of symmetry...
While, boat conformer is achiral as it possesses a plane of symmetry...
Twist boat conformer is chiral as there is no symmetry element...

So, correct answer is "Twisted boat"...

$$Hope it's help...$$

Cyclohexane is a six-membered carbon ring compound with the molecular formula C6H12. It can exist in different conformations due to the rotation around its carbon-carbon bonds. These conformations include chair, boat, and twisted boat conformations. The chirality of a molecule refers to its ability to exist as a pair of non-superimposable mirror images, known as enantiomers.

The chair conformation is the most stable and common form of cyclohexane. It is named so because it resembles a chair-like structure. In this conformation, all carbon atoms are coplanar, and the hydrogens attached to them are in staggered positions. The chair conformation is achiral, meaning it does not exhibit chirality because it possesses a plane of symmetry that divides the molecule into two identical halves.

The boat conformation is another possible conformation of cyclohexane. It is named so because it resembles a boat shape. In this conformation, two carbon atoms are forced to be in a slightly higher energy state due to the interaction between the hydrogens attached to them. The boat conformation is also achiral since it possesses a plane of symmetry that divides the molecule into two identical halves.

The twisted boat conformation is a distorted form of the boat conformation. In this conformation, the boat shape is twisted to relieve the steric strain caused by the interaction between the hydrogens attached to the two carbon atoms in the boat conformation. The twisted boat conformation is chiral because it lacks a plane of symmetry. It exists as a pair of enantiomers that are non-superimposable mirror images of each other.

In summary, the correct answer is option 'C', which is the twisted boat conformation. It is the only conformation of cyclohexane that exhibits chirality.