Explanation:

Monochlorination of 2-methylbutane will result in the formation of a mixture of products. The total number of chiral compounds formed depends on the number of chiral centers present in the molecule.

1. Determine the number of chiral centers in 2-methylbutane:
- A chiral center is a carbon atom bonded to four different groups.
- 2-methylbutane has one chiral center at the second carbon atom.

2. Determine the number of possible stereoisomers:
- For each chiral center, there are two possible stereoisomers (R and S).
- Therefore, there are two possible stereoisomers for 2-methylbutane.

3. Determine the number of possible monochlorination products:
- Monochlorination can occur at any of the four carbon atoms that are bonded to a hydrogen atom.
- Therefore, there are four possible monochlorination products.

4. Determine the number of chiral compounds formed:
- Each monochlorination product can exist as two stereoisomers.
- Therefore, there are a total of eight possible stereoisomers for the four monochlorination products.
- However, only two of these stereoisomers are chiral (have a non-superimposable mirror image), since the other six are achiral (have a superimposable mirror image).
- Therefore, the total number of chiral compounds formed is four (two stereoisomers for each of the two monochlorination products).

Answer: The correct option is B (4).