Why is Wurtz reaction not preferred for the preparation of alkanes containing odd number of carbon atoms?

Why is Wurtz reaction not preferred for the preparation of alkanes containing odd number of carbon atoms? Illustrate your answer by taking one example.

For the preparation of alkanes containing odd number of carbon atoms, two different alkyl halides are taken and two different alkyl halides can react in three different ways. Therefore, a mixture of alkanes is produced,

That’s why this method (Wurtz reaction) is not suitable for the preparation of odd number alkanes.