Chirality in Organic Compounds:
Chirality is a property of certain organic compounds that have a non-superimposable mirror image. A chiral compound exists in two forms known as enantiomers, which are mirror images of each other but cannot be superimposed. In other words, chiral compounds have an asymmetric carbon atom (also known as a chiral center) that is bonded to four different groups or atoms.

Heptanols:
Heptanols are a group of organic compounds that contain a chain of seven carbon atoms with an -OH group attached at different positions. To determine whether a heptanol is chiral or not, we need to examine the carbon atom to which the -OH group is attached.

1-Heptanol:
In 1-heptanol, the -OH group is attached to the first carbon atom of the heptane chain. However, the first carbon atom is not a chiral center because it is bonded to three hydrogen atoms and one methyl group. Therefore, 1-heptanol is not chiral.

2-Heptanol:
In 2-heptanol, the -OH group is attached to the second carbon atom of the heptane chain. The second carbon atom is a chiral center because it is bonded to four different groups: -OH, a hydrogen atom, a methyl group, and a propyl group. Therefore, 2-heptanol is chiral.

3-Heptanol:
In 3-heptanol, the -OH group is attached to the third carbon atom of the heptane chain. The third carbon atom is also a chiral center because it is bonded to four different groups: -OH, a hydrogen atom, a methyl group, and an ethyl group. Therefore, 3-heptanol is chiral.

4-Heptanol:
In 4-heptanol, the -OH group is attached to the fourth carbon atom of the heptane chain. The fourth carbon atom is not a chiral center because it is bonded to three hydrogen atoms and one butyl group. Therefore, 4-heptanol is not chiral.

Conclusion:
Based on the analysis above, we can determine that 2-heptanol and 3-heptanol are chiral compounds because they possess a chiral center. Therefore, the correct answer is option 'B' - 2-heptanol and 3-heptanol.