Why would using all six characters of the POSTCODE attribute be suboptimal?

Why would using all six characters of the POSTCODE attribute be suboptimal?

• A. It would generate many groups, each with a small number of features.
• B. It would generate few groups, each with a large number of features.
• C. It would generate few groups, each with a small number of features.
• D. It would generate many groups, each with a large number of features.

Answer: (A)