Consider the following statements about the Eastern Coastal Plains of India:

I. In contrast to the West Coastal Plains, these are extensive plains with an average width of 120 km.

II. This plain is known as the Northern Circars between the Mahanadi and the Krishna rivers.

III. A major part of the plains is formed as a result of the alluvial fillings of the littoral zone.

Which of the statements given above is/are correct?