Consider the following statements with respect to Settlements:

a. The Clustered Rural Settlement is a compact or closely built-up area of houses.

b. In Semi-Clustered Settlements one or more sections of the village society choose or are forced to live a little away from the main cluster or village.

c. The Urban Settlements are generally compact and larger in size and engaged in a variety of nonagricultural, economic and administrative functions.

Which of the above statements are correct?